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The PAMPA Gallery is now an archive and is no longer accepting uploads.

 

This following list has been suggested by Allen
Brickhaus. All these articles are available as re-prints from PAMPA Products:

Bob Gialdini's Olympic

Jim Young's Bellanca

Cris Lella's Model Aviation stuff on the the three columns on the three axis of models and planes

Ted's Excitation

Paul Walker's Impact

Al Rabe's Mustunt, Mustang and Sea Fury text and pictures

PAMPA Products available at pampacl.org or send inquiries to Pampa Products

Oh my God, the rice is blue!


Feeling guilty after several days in my work shop, I decided to make my wife a nice dinner. The menu included marinated chicken breasts on the grill, steamed vegetables and white rice. As I called her to dinner, I poured the wine and placed the platters on the table. As she entered the dining room, I was getting ready to put the rice into a serving dish when to my surprise, the rice
was blue. Not just a little blue, Corsair blue!

Actually, this story had its beginnings far too long ago when I began to build a Randy Smith Dreadnought.
Late into the construction, I decided to re-carve the cowling, re-cut the vertical stabilizer, turn around the canopy and make it into his Tempest II. For the canopy, I took a 10 inch bubble canopy and turned it backwards. After much fitting, I was able to get a very slick looking canopy. The next step was to see what colors I had around the house to dye it. From past experience, the powder
dyes don't completely dissolve, so I try to use the liquid when possible. I had one bottle of black, and one box of blue powder. The black will sometimes look green, so I knew I would need to add some of the blue to achieve a pleasing tint. I also did not want to take any chances with undissolved color, so I made sure the solution got very hot.

This is when all the fun began. I transferred the solution in its pot from the stove to the sink so that I would not make a mess on the stove and clean running water would be nearby. All of the
Rubber Maid sink accessories were carefully set aside, as were the curtains tied back to be clear of all splashes. I then carefully lowered my painstakingly shaped canopy into the solution where it instantly curled into a straw. Thoroughly disgusted with myself, I quickly cleaned my mess and headed to the hobby shop for another canopy.

Curt's Quick Tinting Tips...

1. Use liquid dyes only
2. Don't over heat the solution as the heat will distort the canopy
3. Tint the Canopy before you cut it out, this will help it keep its shape
4. Wash all pots and tools several times with soap before attempting to cook rice.

About a year and a half ago, I was fortunate enough to inherit a complete set of the Rapidograph technical pens - or so I thought. Upon closer scrutiny, it became obvious that these pens were in
SAD shape. The previous owner (no relation) had put them away with the reservoirs FULL of ink. Judging by the hardness of the ink, this must have happened some time in the early 70’s.

I was absolutely determined to clean them since I wanted to try ink lines on my new ship and had no intention of spending the big bucks on a full set of these babies. To make a long story
short, I tried everything to clean them and I finally succeed in restoring them to like-new condition. What follows is a brief summary of a method that really works.

Step 1. Fill a sink with hot soapy water and clean each individual part of the pen as well as possible. Most of the parts clean up fine, but the problem is the actual metal tip. It was welded in place with dried crusty ink. When I shook the tip, there was no detectable movement of the valve.
Gently clean the tip with a toothbrush to remove as much caked on ink as possible. If the tip rattles when you shake it back and forth, you are home free. If it doesn’t, proceed to step 2.

Step 2. Fill a clean glass jar with a 50 / 50 mix of Windex and rubbing alcohol. Any chemists in the
audience can feel free to comment if I’ve created some form of deadly concoction here. This reminds me of a story of creating chlorine gas while mixing a bucket of mop water at McDonald’s…but I digress. I believe the "secret" ingredient in this mix is the ammonia in the Windex, but I’m not really sure. I haven’t experimented with just Windex, but it may be even more effective. This mixture
causes the dried up ink to liquefy when you soak the tip in it. This enables you to get the needle valve out of the tip by CAREFULLY pulling the weight out of the back of the tip. Anything else that I tried, including the pen cleaning solution, was completely ineffective. As with anything involving chemicals, take appropriate safety precautions like adequate ventilation, and make sure you test
the solution you create on the plastic of the pen before soaking them. As a general rule, it shouldn’t take more than 30 minutes of soaking to really make some headway.

Step 3: Using EXTREME care, disassemble the tip. The finer the pen, the more care that must be exercised when removing the valve. What can happen is that you get the weight part of the valve out, but leave the wire part that fits into the barrel of the pen still stuck in the barrel. What
sometimes works in this instance is to soak the tip a little more, dry the weight as well as possible and then gently press it back onto the wire in the hope that you can seat it in the weight well enough onto the wire so that the force required to remove the wire from the weight is greater than the force
required to remove the wire from the barrel of the pen. If this fails, I know of no way to get the wire out of the barrel, which renders this tip useless.

When you have the needle valve out of the pen, put it and the tip back into the cleaning solution for a few more minutes. When it comes out, dry it off with a paper towel and blow compressed air through it from both directions. It’s just like cleaning a spray gun; you must remove every trace of
the dried ink, or the pen will never work properly. Bingo, that’s it.

I hope that others can benefit from my frustrating experience, but I don’t expect for this tip to be of much value since anyone who actually works for a living and buys one or more of these pens would EVER put it away without cleaning it…..right ??

I was coming to the end of the ink line work on my new Buccaneer (yeah, I know I’m a little slow), and it came time to do the fuse. So far, everything was working great. I put a couple of lines on
each side of the fuse in front of the wing. This looked great, but I could see no easy way to join the lines on each side accurately with a line over the topblock. I knew that a flexible straight edge was required, but I didn’t have one that was flexible enough.

After some scrounging around the shop, I came up with a clear sheet of plastic that had letter stencils cut out of it. I had purchased it with the intent of hand stenciling on the lettering. It’s just
clear plastic .010" thick, with a nice straight edge. I just put about 4 layers of masking tape along the long edge to prevent ink from bleeding under it and presto, I’ve turned a useless stencil into a priceless tool for a good looking ink line job.

If you don’t want to buy a set of stencils for this, you could try using overhead projector transparency film. It is .004" thick and may not have quite as good an edge on it, but it’s a possibility.

This probably comes as no great revelation to the more experienced folks, but it was
new ground for me and I thought I’d share it.

To greatly ease the process of tying off the ends of your control lines (you're not using ready-to-crash crimped lines are you?), purchase a fly tying vise from a fishing tackle supply store or catalog. The vise is easily attached to a table or chair arm, and neatly holds the eyelet, leaving both hands free to wind on the wire binding, per AMA Rule Book. The fly-tying vise is small enough to carry in a tool box or contest supply box for field use. Price is around $10 to $12

Nearly everyone uses Epoxolite from SIG for making fillets. A problem with this stuff is its tendency to form "granules" in the brown part (can't remember if it's "A" or "B", sorry) from extended time on the shelf. When used in this form, it's like making fillets out of sand -- it works, but isn't pleasant to use.

To fix the problem, put the package of brown stuff into the microwave for about 1-1/2 minutes on "high". Loosen top, but leave it resting on the container to prevent any spattering inside the microwave. Result is an almost watery liquid which dissolves all the granules. Stir thoroughly to be sure. When re-cooled, it will be butter smooth. However, I like to mix up my working Epoxolite while the brown stuff is still warm and liquid, as it makes blending the two parts much easier.

After opening new Epoxolite a couple of times, only to find "rocks" after I'd mixed the two parts, I now routinely "zap" the brown part before any use. I suppose application of a heat gun or placing the container in boiling water would work too, but the microwave is certainly quicker. When using this stuff in "liquid form", it's handy to use one of those little plastic medicine cups to get exact
measurements - available at most hobby stores as "epoxy mixing cups", or from the top of a bottle of Nyquil, or similar Maybe your druggist has them too?

Most Balsa suppliers sell triangular stock. Just glue a strip to the square leading edge and your are done!

My current finishing method is Certified or Randolph color with automotive toners added to get those colors no available off the shelf, talc filler/sanding sealer and final coat of Automotive
Clear coat. The result has been 18/19 points under some very critical judging.

Here's the process:
Sand all bare wood smooth with 320. Apply 2 brushed coats of Clear thinned 30%. Sand lightly with 600. Cover all wood with .02 oz. carbon veil. Apply 2 more brushed coats of the same clear mixture. Again sand lightly with 600.

Pour some full strength clear in a large container with a good sealing lid. Now dump in as much Talc as will stay suspended in the dope (allow about 10 minutes to settle) Next, very important step is to mix in a small amount of Black dope, just enough to make a very light gray. The very best Talc I have ever used comes from Tap Plastics. It has no odder or oils. Next, thin this mixture only enough to get it through your spray gun. I use a big ugly gun with pressure feed, they're cheap and readily
available at Sears. Spray on a medium heavy coat of this stuff. Let it dry a day. Now here's the really cool part. You're gonna sand off 80 to 90% of this and you'll hardly break a sweat! This stuff powders like crazy! It took only 3 hours to sand an entire classic ship leaving only enough to fill. Now since this mixture is gray you will be able to tell the low spots and areas that need more
work. No need to get out the spray gun, just spot these areas with a brush and sand. Once everything is uniform thin some clear dope 80% that right 80% and spray on a quick wet coat!

Color: Thin all colors 50 to 60% with and spray on dry. Just enough to cover, don't worry about shine, blushing or even being a little rough. Once all colors are on. Spray on 2 coats of clear thinned
60%. Again don't worry about shine or blush. Lightly sand everything with 800 wet being careful not to sand through the clear coats. Finally once everything is sanded CLEAN EVERYTHING WITH WINDEX. CLEAN IT AT LEAST 2 TIMES USING WINDEX.

I usually do this procedure 4 times. Degreasers such as Prepsol or AcryliClean don’t get the job done. What you really want to do with cleaning is remove everything that is not fixed permanently to the surface. The reason for all the cleaning is I discovered that just about all of the dust particles that end up in the clear coat are on the plane to begin with. Very little comes from the air. Once you have cleaned and re-cleaned go over everything with a tack cloth several times being careful to apply only light pressure.


Now you’re ready for the main event. Lightly apply 1 coat of Automotive Clear. I use PPG Global
Performance System Clear D893 and D871 Medium thinner/reducer (this is very different stuff from the DAU 75). This is a 3-part paint, clear, catalyst, and reducer. I use 50% reducer to get a water thin mixture. I also use a gravity fed touch-up gun to put on a very light but even coat. The PPG is dust free in about 10 minutes and the model can be handled in about 2 hours. Your plane will shine
like glass at this point and depending on how much dust you have in your spray area you just might be finished! If there is dust fear not. Wet sand with 1200 or 1500 (which ever you have the patience for) and rub out. This whole process added 9 oz. to a fairly large 750 sq. piped ship that has a lot of fuse, rudder and cheek cowls. It only took 6 oz. for my Vulcan classic ship. While I've heard of 4 to 6 oz. finishes by others I have never been able to get it that light no matter how hard I try. The weight of this is quite reasonable and very fast and easy. Hope this helps.

Buy some cheap lacquer thinner from the home supply store of your choice. I have tried Acetone, and I have tried retarder, cheap thinner works the best. Next, buy a couple of rolls of Bounty
Select-A-Size paper towels and a charcoal mask - you should have one anyway.
Tear off 20 or so sections of paper towels and make a flat pile. Take one Bounty Select-A-Size square and fold it in half three times, then tip the gallon of thinner with the towel over the top.

With a wet, but not dripping towel, wipe on a small area of the model, about a 6" square. As you wipe, open the towel, re-fold it, then continue to wipe on the same area. When it seems like the towel is no longer working, it will still be wet, but saturated with dope. Throw that towel away and repeat the process.

You will also be able to remove the paint that is down in the hinge lines this way too, just be very
careful around the hinges when there are foam flying surfaces. I used the same paper towels and Q-Tips to get the hingelines cleaned, just don't rub too hard as the Q-Tip shaft can dent the wood.

You will find that the paint comes off in layers, and you can stop at any point. I took mine down to the paper, however I could nave gone farther, or stopped sooner. When you are done, you
have a smooth finish that re-finishes easily.

It will not take long for you to get the hang of it and establish a pace that works. It took me about 30
minutes per wing panel to completely remove all the finish, down to smooth paper. I decided to re-cover the wing bays, so I left the open covered areas alone and then cut them out after the paint over the cap strips and sheeting was removed and then lightly sanded the edges with a foam core nail file.

The reason I decided to re-cover the wing, was because I felt I would avoid any problems where the paper had been weakend on the edge of cap strips or sheeting from the previous finishing process. I also felt that the model would finish quicker that way.

It took me a total of 3 hours to remove the entire finish from a 60 sized 680 square inch airplane. Once stripped, I let it sit for three days to gas off and dry out. Once dry, I sanded it lightly, gave it one coat of clear, and recovered it. The new paper filled much quicker than it would have over bare wood. Had I not had to make modifications to do on the fuselage and tail, there would have been no reason for me to do anything to the fuse after one hour of stripping other than to re-paint it.

I did not invent the method, Frank McMillan and Randy Smith both told me it would work. I wrote a
column about this method in Model Aviation, and several people have told me theytried it after reading about it and were amazed how well, and how quickly it worked.

With sanding, you always run the risk of cutting too deep and making a mess. I will never do it any other way than with thinner. Give it a try on an old wrecked model first - that is why you should "Save the pieces" as Phil Brown would say.

I have been asked to make a post on how to convert a glow powered stunter to electric, so here is a short write-up giving you a starting point. This will also work for a scratch built electric model and in turn will be easier than doing a conversion. Converting an exsisting airplane is not the ideal situation because more than likely there are areas that are over built, oil soaked, or are going to need to be modified to accept an electric power system. Also, batteries may be hard to mount depending
on balance point and room constraints.

To determine whether or not the airplane can be sucessfully converted follow these steps.

1) Determine the target weight ready to fly. (My example will be a .40 size stunter.) The target weight I chose is 46oz. I will set this as my upper limit.

2) Now you need to calculate the power needed to fly the stunter at a satisfactory performance level. We want a minimum of 160-170 watts/lb input. We have a 46oz stunter or 2.875lbs so we are looking at 2.875lbs x 160 watts/lb = 460 watts input power minimum.

3) Pick the current draw you want the power system to run at and then divide the total number of watts needed to fly the stunter by this number. I will use 35amps, so 460watts / 35amps = 13.14. This number is the minimum number of volts you will need to get the power input we are looking for.

4) So now we know to fly a 46oz model we will need to draw 35 amps from a battery source of at least 13.14volts. Since we are using Li-Poly batteries we have to choose packs with voltages divisable by 3.7. Each Li-Poly cell is 3.7 volts so 13.14 volts / 3.7volts = 3.6 cells. Remember we are using minimums to calculate our setup so we don't want to drop down in cell count, so we will round up to a 4 cell pack. Most packs on the market with discharge rates high enough for our use are 2P packs or 2 cells in parallel. Putting the two together gives us a 4S2P pack. (the number of cells parallel depends on the C rating needed)

5) Now that we know what we are looking for we can decide on what motor and battery combination to use. This is where things become more difficult. The selection may seem endless when it comes to motors, so how do you know which one to pick? If you read up on electric power systems you will find the most popular or best performing motor brands. (Ex. AXI, Plettenberg, Aveox, Hacker, Jeti, Mega) to name a few. I have used mainly AXI and Plettenberg outrunner style motors from the beginning. There are also a number of motors that are the conventional "inrunner" style that will work well, but I found good results with outrunners so I have stuck with them for the time being.


Batteries are the same situation. There are many good brands out there and if you follow electric power at all you will pick up on them. I prefer Thunder Power because they seem to have the highest energy density per weight, and also have proven to be extremely reliable.

6) After you decide which brand or brands you want to look into you need to determine what size motor will handle the voltage you will be using. We are using 14.8volts or 4S Li-Poly pack. Motors are normally rated at a min and max voltage, max continuous amperage, and max efficancy @ a given current level, or at least that is what we will be looking at mainly. We need to be sure we fall in between them.

As far as the battery pack goes you need to be sure it is a 4S2P (for this setup) and can handle the 35amps continuously that we will be drawing. Do not pick a pack that says it can handle 35amps continuous and say 50amps for short bursts. We want some room for error and a little safety cushion so look for a pack that can handle at least 40amps continuously. This will let you pull more current later if needed and also keep the pack from working at it's limit extending it's life and keeping it cool during use.


7) So you have picked the motor brand and size that will handle our input voltage of 14.8volts. For a .40 size stunter we will be using a 10-12" prop with a pitch of 4-6" more than likely. I will pick an 11" dia and a 4" pitch. (I prefer lower pitch props, but you can use what you prefer) Now you can either look up the manufacturers specs for the motor (they usually give you a few examples of performance levels for a given prop at a given voltage) or you can buy a motor calcualtor program to help you along (motocalc is an example). Lets say the first motor you choose turns an 11x4 @ 14,000rpm and draws 47amps. The first problem is the rpm. It is to high for our application and the current draw reflects this. To fix this we will need to pick another motor (same size and manufacurer) with a higher number of winds. The higher the number of winds the lower the rpm for a given voltage. This will also lower the current draw if you keep the input voltage constant. You would do just the opposite if the motor turned to few rpm. If you go through each motor in that size range (from the same manufacturer) and you still can't find one suitable for your application you will need to vary the prop dia. and pitch to adjust the pitch speed and amp draw until it is usable. If you can't get it to a satisfactory level you may need to change motor manufacturers. Even though two
different motors have the same size, weight, number of winds etc.... they may still perform differently. The reason being different manufacturers hold different tolerences, use different materials, have different designs and so on...

8) Ok, we now know our target weight, power system requirements, battery voltage needed and amp draw that is required. We are pretty sure the motor we picked is what we need or is close enough that a few prop adjustments will get us there and the battery pack will deliver the power. That leaves us with an ESC and timer.

ESC's for the most part all perform very close to one another. A few examples are Castle Creations and Jeti. The biggest difference is the programming options. All you really need to be concerned with is that is capable of handling the current levels we will be pushing, has a governor and has a BEC built in. I recommend like the battery going a little higher on the rating than needed. For a 35 amp setup go with a 40 or 45 amp controller. Again we don't want to push the system to the limit and cause heat problems. Just like an IC setup to much heat is bad for electric power systems
as well. The governor will be used as a break to prevent whip up. The BEC is short for battery eliminator circuit. This will be set at the appropriate voltage incase of any type of timer failure the ESC will shut the motor off to prevent damage to the battery pack or airplane. I won't go into detail because each pack 2S 3S 4S 5S etc... needs a different cutoff voltage and each ESC is different when it comes to programming.

Timers are limited right now to the Z-Tron and the JMP. I only have experiance with the Z-Tron timer and can say it works very well although the JMP has gotten very good reviews as well.


9) Now we know the motor, battery pack, ESC, timer and prop to be used. Now you can weigh the entire setup and add a little extra for the connectors, solder, shrink wrap, prop, prop adapter, timer and other misc mounting hardware. When your total is tallied subtract it from your ready to fly weight. I will call this setup weight 22oz. 46oz - 22oz = 24oz bare airframe weight.

I am sure you can guess what to do next. Pull that engine, prop, tank, fuel lines, filter, etc... out of the airplane and weight it. Above 24oz and you may be a little on the heavy side. 24oz or less and you are on your way to a successful conversion. If you are close to the weight you may want to pull the engine beams/crutch assembly and tank mount/floor out to get you to your target weight or maybe even below it. Don't forget to pull out any nose or tail weight. You will be able to shift the battery to compensate for the added balast previously needed.

If you are using this step by step for a scratch built project you can build the model to suit the weight needed making it easier on yourself.

Like I said earlier this is just a quick rundown on how to get started. I didn't really go into any detail on any one subject. Electric power systems have so many variables one could write page after page about them. There is still a lot of theory behind it all (for C/L use) and there are many things I still don't know myself. Also, the figures I used may not hold true. They are just examples to show the math involved.

I think this will give you a good starting point on designing your own power system. I am sure I missed some things, and may have even been a little off on somethings I mentioned. I apologise ahead of time if I did.

Mike

Introduction: Over the last 25 years, the choices of covering materials for R/C models have expanded steadily. So why is it that some "old timers" still cover models with old-fashioned
silkspan? Well I'm not exactly an old timer, but I can think of four reasons. Covering with silkspan is: 1) easy, 2) cheap, 3) fun, and 4) beautiful! Silkspan is lightweight, accepts nearly all paints readily, and will never ever sag, bubble or wrinkle. It goes on just as easily over either sheeted structures or
open framework, and even repairs are a snap.

While generally used on smaller models like Old Timers, 1/2A glow and small electrics, silkspan is also an excellent surface prep for sheeted surfaces even on giant scale warbirds. It's an excellent choice for applications like simulating fabric-covered control surfaces. Be forewarned though, silkspan is easier to tear or puncture than most modern coverings, but it's also extremely light.

Please note that the nitrate dope used for applying the silkspan is not fuel-proof. If the model is
going to be exposed to fuel, you'll have to use a fuel-proof paint like butyrate dope, epoxy, polyurethane etc. over the nitrate. For electrics or gliders, you can use whatever you like for the color coats. Another nice technique is to color the silkspan with household dye before applying it. The options are almost endless.

1. Materials: The required materials include: sheets of silkspan (for all but the smallest models, I use medium or heavy material), nitrate (not butyrate) dope, dope thinner, water, 2 or 3 brushes, talcum powder, 240 and 400 grit wet/dry sandpaper.

2. Surface Prep: After finish sanding the airframe and removing all dust, brush 2 to 3 coats of 20% thinned nitrate dope on all surfaces that will contact the covering. Sand the airframe lightly with
240 sandpaper between coats. You want a reasonably water-proof seal so the balsa will resist warping when you apply the wet silkspan.

3. Application: I recommend starting with the bottom of the wing, as it's the easiest surface to
cover. Lay the wing on a clean work surface and trim a sheet of silkspan to size so that there's 1 to 2" of excess around the perimeter. Brush the sheet of silkspan with water until it's completely saturated. This will cause it to swell and wrinkle.

4. Trimming: Start lifting and smoothing the silkspan until all wrinkles are removed and it's pulled fairly taut. The wet brush will help you to force bubbles to the edges. Be careful not to tear it, but even wet, it's surprisingly tough. Wet a piece of 240 wet-dry sandpaper, and sanding on the
downstroke only, feather away the excess silkspan. You'll find you can easily work around compound curves and can wrap the material around the leading edge and wingtip.

5. Doping: Once the silkspan is trimmed, and while it's still damp brush on a coat of nitrate dope that's thinned 50%. The dope is this highly thinned because you want the thinner in the brushed-on dope to partially dissolve the dope that's already on the bare balsa. This will bond the covering
to the airframe. At this stage, it will look mottled, whitish and ugly, but all will be well once it's dry.

6. Continue Covering: Continue to cover the rest of the wing and then the fuselage following steps 2 thru 6, overlapping the successive pieces so that there are no gaps. If you tear a sheet or can't get it
to lay properly, just lift if off and try again with a fresh sheet. Apply a second coat of thinned dope to the covered airframe to make sure the silkspan is fully saturated.

7. Additional Coats: Once the entire airframe has been covered and doped into place, allow it to dry thoroughly. As it dries, the silkspan will turn a uniform white color and will pull nice and taut. Next,
brush on 2 to 3 additional coats of dope, sanding very lightly between coats with 400 or finer sandpaper. Be careful not to sand through the silkspan, especially over open frame.

8. Mixing Filler: To fill the weave preparatory to painting, mix regular talcum powder into your thinned dope until you have a slurry. You'll have to acquire a feel for how much to use; too little
and it doesn't fill very well and is harder to sand; too much, and the filler will be porous and won't take a smooth paint surface. The right mixture has the consistency of watery wallpaper paste.

9. Filling: Brush the talcum/dope mixture onto the model and allow it to dry. Work quickly, as the mixture will set up in a hurry.

10. Final Sanding: Lightly sand the airframe. Note that the talcum is not only easy on your skin, it smells lovely as well! If you can still see rough spots, repeat steps 9 and 10. That's it! The airframe is now primed and ready for the paint finish of your choice.

11. A NOTE ON REPAIRS: When patching holes or repairs, tear the silkspan patch instead of
cutting it with scissors. A ragged edge is much easier to blend into the surrounding surface than a cut edge. Simply tear the patch to size, lay it in place, wet it, and dope it down. After the patch dries, apply 2 to 3 coats of thinned dope, sanding between coats. Then fill, sand and paint the patch. Wasn't that easy?

Conclusion: This covering technique is lighter than nearly any film, will never wrinkle, and is quite easy to do. There's no trick to it!

Here's the drill:

Get yourself a bottle of LIQUID fabric dye - RIT, Tintex, whatever.
Pour about one third the bottle into a clean glass jar.
Microwave the dye until it is hot to the touch - not boiling.
Toss in the nylon parts and go have a beer, waiting till it cools to room temp - at least one-half hour (OK, have two beers)
With tweezers, remove the parts and drop them into warm water.
Pour the remaining dye back into the bottle - you can use it over and over.
Rinse off the parts and admire the new color.
Experiment to make parts darker or lighter.

We have incorporated Fuel Filters into our program in an attempt to add a little more longevity to our motors. The important thing with these fuel filters is to check them regularly. Countless times we have had a problem with the motors not wanting to needle properly and checked the filter only to find that it was the culprit. You can break the filter apart, and when you see what is in there sometimes you are glad it did not go into the motor.

We use Master Airscrew Fuel filters. They are small, blue single screen filters and have been known to leak, but they seem to fit the best in our models, and if we suspect them they are cheap enough that you can throw them away and put a new one on.

One thing I have done in an attempt to prevent these from leaking is take some thick CA and run it around the seam, then wipe the glue with a paper towel, making sure you spread the globe around the seam. You could maybe heat the seam and cause it to tighten up, but I have not tried that. Another possible idea is heat shrink tubing.

Another thing we have used and like is the black rubber air filters that fit around the venturi. These house a changeable filter. The only two filters I have seen are a black one and a green one. The black one is a little more course, than the green. One must remember that these do reduce the
venturi size, so you need to take that into account. It is said that the black insert reduces the opening by 0.005 and the green insert reduces the opening by 0.010 we have actually used this as a trim feature allowing us to decrease the venturi ID without having to re-drill the opening.

Cut a round patch of panty-hose matrial larger than venturi opening, stretch it over venturi opening, then slide one or two proper sized rubber "O" rings over the venturi to secure the "filter". (Shamelessly stolen tip from Richard Oliver.)

I don't like the yukie silver color of the APC nylon prop. If you would perfer black as I do, just soak the prop in about a quart of very hot water with a whole package of black Rit dye for about two or three hours. You will then have a nice black prop.

Take care, Dee

I've seen a couple of things I'd like to comment on.

First is the reality that this is a horsepower maneuver. (by the way I wrote a couple of long two part articles on flying the pattern a number of years ago that discusse the design and trim of airplanes to
fly the pattern. I think they were called the Design and trim of CL Stunt Models or something similar If all the numbers (weight, engine, prop. etc.) say power isn't a problem you need to look at how you're wasting energy. In this case all the energy you're interested in is coming from thrust. Part of this thrust is the energy stored in the vehicle and part is that available from the power train. What is the enemy of thrust? The simple (and correct) answer is "drag". These are the opposing forces at work.

Drag is generally of two forms. "Form drag" which is produced by the shape of the object you're trying to haul through the air and "induced drag" which is the result of producing lift. Increase either unnecessarily and you've thrown away energy that must be replaced by the power train while you're in an inverted climb.

Don't do that!

How do you maximize the energy in the vehicle and minimize the loss thereof. You have to minimize the drag in level flight and use no more lift than necessary to enter the climbing portion of the 'glass than necessary to convince the judges you have, indeed, entered the maneuver.

This means in the first case your airplane has to flying as cleanly in level flight as possible. A
straight airplane flying as tangent to the circle as possible. For good info on this read pretty much any of Brett Bucks posts regaring yaw trim, leadout position, rudder offset, etc. If any of that is wrong you are throwing away thrust/energy you could otherwise use to fly that hourglass.

In David's case I'm not real enthusiastic about the leadouts being just 1/4" aft of the CG.
Theoretically on a conventional stunt ship in good trim this is too far forward.
It is likely masking some other trim deficiency in the airplane and I'll bet bucks on Buck figuring that one out. He's a genius on that stuff.

To control the other form of drag, induced, we want to minimize the drag buildup in the entry to the 'glass. High "g's" mean high drag. Tight corners mean high "g's". If you hammer the entry you're going to throw away energy that even the strongest powertrains might have trouble returning to you given the fact that you've just pulled the airplane into a past vertical climb (the angles of which tell you you've maintained that high g high drag configuration for a comparatively long duration).

Ergo (pontificatorese for "therefore), fly that first corner no more aggressively than you can do without obviously depleting your energy...and certainly no more than experience tells you you can
throw at the engine and hope to get back by the top of the maneuver.

Here's a trick, if you're ship is obesity challenged and you don't want to make the entry look like a big bagel, add some energy during your entry. You can do this easily by starting with your arm extended to its fullest and, as you start the entry move your arm toward your body and simultaneously take a step back while giving a control input appropriate to the corner you hope
to fly. Both of these motions would get you a "foul" call from a team race official because in that venue what you are doing is called "whipping". Whipping is nothing more than racing talk for "adding energy to the airplane or, making it fly faster". In our case, of course, what you are doing is minimizing the loss of airspeed from our sustained high "g" induced drag.

At the top of the circle when flying the second and third corners be very aware of the same risks of throwing away energy. Too many people "hit" the second or third corners which throws away energy at a really difficult point because the wing lift is acting horizontally and gravity is sucking the airplane down. You've got to keep it flying. Think of "flying" into and out of these corners, not banging them.

Finally, the worst mistakes I see in hourglasses is poor shapes and vertical lines plus the top is seldom parallel to the bottom. This is usually the result of overturning the first corner which makes the climb too flat and makes the top impossibly long (usually resulting in an early third corner
overhead instead of to the pilot's left). If they get the climb right all too often the second corner is not held long enough, the airplane flies behind the pilot and he finds himself making one huge split ess to get back to remotely where he started without crashing).

This is almost always because the pilot loses (or never thought of having) any reference to help him define where the corners should be and where the straight lines should head.

I suggest using your body as a reference. Plant your fit facing directly downwind (the center of the maneuver). Start the maneuver by pulling up at your left toe, climb in a straight line to your right shoulder, fly into and out of a 120degree turn to fly directly toward your left shoulder and, when you get there, fly into and out of another 120 degree turn toward your right toe. Finally fly a nice
straight line toward that toe and casually pull out of the resulting inverted dive at four to six feet...without a bobble, of course.

The secret to this is to never turn your shoulders while performing the maneuver and to minimize any turning of the head. You must keep your body in theproper relationship to the desired maneuver in order to use the body as a reference. Make sense?

By the way, the more vertical you make you hourglass (most turn the entry way too far and flatten the resulting manevuer to the point that the dive is nearly inverted flight) the easier you'll find that fourth corner (you know, the one the judges are just waiting for you to screw up)to fly with precision.

So, what you need is a "properly" trimmed airplane sucking the least possible energy out of an adequate or better powertrain flying the maneuver in such a way as to waste as little energy as possible while still flying the precise shape by using your body as a reference and, if you need a
little "oomph" toss it in at the entry with a gentle but positive "human invigoration" of the energy equation.

Wow, it's a good thing computers don't use ink, huh.

2017 Issue 3 of Stunt News is available for download to current PAMPA members


The 2017 Issue 3 of "Stunt News" includes:

Vintage Stunt Championships
by Jim Hoffman and Steve Holt

Bucks 550 Electric Power Retro-Fit by Joe Adamusko
Twin Nacelle Alignment
a Stunt News How-To by Bob Hunt

- Plus District and International Reports, Contest Results, and much more.

To download the latest Stunt News, make sure you are logged into the PAMPA Website and click HERE.

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