Building Techniques: Barnstormers Pattern Site

Installing a Violett Hatch Mount: Always install the mechanism with the spring and pin on the fuselage and the female receptacle on the canopy. Reason: the pin won't damage the finish when you repeatedly install the canopy. Don Ramsey

Honeycombing - When honeycombing a wing always provide an escape for the air trapped in the honeycombing. Use small holes and vent to some outside area, the wheel well, the wing root area, etc. This will keep the air in these holes from expanding and contracting when in the weather. Mike Harrison

6-32 Control Horns - Foolproof and durable control surface control horns. I use 6-32 x 2" Stainless steel phillips head screws. Counter sink into a hardwood dowel epoxied in the control surface. On the Bottom, reverse a blind nut, attach and tighten with loctite, grind off the tangs. Use the Goldberg nylon connectors - they screw on great, easily replaced, and stay put. The "trick" in this is the drilling of the hardwood. I drill the screw hole in the dowel BEFORE beveling the leading edge. That way, you can "square" the leading edge to a 90 deg block, then just drill a vertical hole...if you use the same block and a drill press, all the holes will ALWAYS be perpendicular to the center line of the airfoil.a necessity for symmetrical throws..... Bob Pastorello

I also use 6-32 Stainless steel screws. But, I pick up some nylon inserts from my local Home Improvement chain. These inserts come threaded or non-threaded, and in lengths up to 1". I try to get the pre-threaded 6-32 ones, drill out my dowel to accept them and CA the threaded inserts in place. That's it!!! The nylon captures the 6-32 bolt securely, will not vibrate loose, and is easily removable for finishing/maintenance. Michael McEvilley.

Building light is tough enough if you know the weight of the materials you are using. If you don't know what's light and what's not, then you don't have a chance. Maybe this chart will help.

Dimension	4 # per cubic ft (Contest Grade)		6 #		8 #
	Ounces	Grams	Ounces	Grams	Ounces	Grams
1/16 x 3 x 36	0.250	7.1	0.375	10.6	0.500	14.2
1/16 x 4 x 36	0.333	9.4	0.500	14.2	0.666	18.9
3/32 x 3 x 36	0.375	10.6	0.563	15.9	0.750	21.3
3/32 x 4 x 36	0.500	14.2	0.750	21.3	1.000	28.3
1/8 x 3 x 36	0.500	14.2	0.750	21.3	1.000	28.3
1/8 x 4 x 36	0.667	18.9	1.000	28.3	1.333	37.8
1/4 x 1/4 x 36	0.083	2.4	0.125	3.5	0.166	4.7
1/4 x 1/2 x 36	0.167	4.7	0.251	7.1	0.334	9.5
1/4 x 3 x 36	1.000	28.3	1.500	42.5	2.000	56.7
1/4 x 4 x 36	1.333	37.8	2.000	56.7	2.666	75.6
3/8 x 3 x 36	1.5	42.5	2.25	63.8	3.0	85
3/8 x 4 x 36	2.0	56.7	3.0	85	4.0	113.4
1/2 x 3 x 36	2.0	56.7	3.0	85	4.0	113.4
1/2 x 4 x 36	2.67	75.7	4.0	113.4	5.33	151.1

For those who don't have a coach but recognize they have geometry problems to correct. On plain white typing paper, draw ACCURATE shapes of the maneuvers you're having problems with. Use as much of the sheet of paper as possible. Make the lines properly-proportioned, angles correct, radiuses round, etc.

Then, hold those shapes in front of you, at arm's length, and use them to visualize the geometric appearance of the maneuver. This may sound kind of hokey, but it WILL make a difference. The arm's length visualization is pretty important. Somehow this gives vertical placement perspective and helps.

-- Don't use butrate dope as a sealer on wing panels before glassing. The dope will outgas over the life of the airplane and may cause blisters on a hot day.

This discussion came from the web site nscra-list@eskimo.com (To subscribe to the list send an email message to: nsrca-list-request@eskimo.com and in the subject line of the message put: subscribe).

How does a flyer go about determining that he needs to upgrade his servos? How do you distinguish between an airplane design problem, a "dumb thumbs" problem, and a poor servo problem? By poor servo I mean in the performance sense. Assume for, discussion, that everything in the plane is functioning normally and that it is as well trimmed as possible. Dave

Here are some things that I look at, especially when flying someone elses plane and they ask for recommendations.

Ailerons: How well do they center. If 1 doesn't center consistently, aileron trim will be effected.

Elevator: Is it smooth throughout the travel. This van be told through a series of 1/4 loops and full loops to see some effect.

Rudder: In knife edge flight, how effective is the rudder? Lower torque servo's will exhibit a condition called blow back, where the force against the rudder is more than the servo can handle. Knife edge loops are a prime example. Also, if they don't center well, major trim problems can develop. For snaps, I like a fast servo. I prefer that the rudder servo be the fastest of all the servo's. Ailerons could be slowest, if I had to choose where to put them.

Another test is just time.... How long before the pots get dirty or they jitter around center. For example, I use 9202's alot, for ailerons on the large IMAC planes, usually 4 of them, and elevator on my pattern planes. 9202's are just abit noisy of a servo, but very reliable, and very inexpensive, about $50 or so.

I went the Hitec route years ago. Not that they are a bad servo, I find coreless servo's are to my liking and quality.

Dave, one method I recommend is to make the decision that your servos are not adequate when YOU can sense the frustration of poor centering, trim wander, asymmetric travel, etc. To go buy servos BEFORE you can notice their benefit means you need more stick time. The reason I suggest this method, is the DEFINITE improvement in your flying when YOU decide the change is warranted....remember, it's your flights..... Bob Pastorello

This discussion came from the web site nscra-list@eskimo.com (To subscribe to the list send an email message to: nsrca-list-request@eskimo.com and in the subject line of the message put: subscribe).

What are the pros and the cons of PCM vs FM. I just got through reading the article in Model Airplane News, where the author doesn't believe there is any great help in Fail Safe, or PCM. Even the PCM proponents admit that FM has better resolution, etc. OK, what do you all think. Is PCM needed, or will FM be just fine in local pattern events

I used to fly a 9VAP on PPM (FM) and the borrowed a pattern plane using my tx on PCM. The difference was day and night. Fail safe is not an issue, but if my plane ever goes into failsafe mode, my retracts drop, that lets me know I've gone into failsafe.

PCM has better signal rejection, and if you do get hit and loose control, the plane will lock you out, and not go wild all over the sky like FM will. I have seen this happen 3 years ago at a pattern meet. On the last flight my buddies Meridian went wild after take off, and it was the longest 45 seconds until it finally went in, and it was all over the place.

I think that most opinions on PCM vs. PPM is based upon past experience, if You once have had problems with PCM You tend to hate it. Don't listen to the Heli-guys, PCM in a copter seems to lead directly to disaster, not comparable environment to a pattern plane.

-Regarding resolution, if the computer in the transmitter is used correctly (not ATV'd to 10% !!) the 1024 steps available on new radios, should be plenty good. Ref JR super servos, has lower angle span for a certain amount of stick usage, compared to other, because you should increase ATV to MAX to fully take advantage of the radios potential resolution.

-Increased noise immunity on PCM is good, what is bad is that even if we are close to loosing control (due to noise), we wont notice it. I would like to have a possibility to hook something into the receiver after a flight, telling me the percentage of garbled messages (hold-situations), it would calm me a lot (or maybe scare me ??)

If using JR super servos, a PPM receiver with RF-noise in air, would lead to jiggling of servos, and a dangerously high power consumption. Meaning : potential crash after a few flights due to low battery (done it !)

Both the PCM and FM receive FM signals from the transmitter, so they are both FM radios. The difference comes in with how the information that goes to the servos is decoded. A benefit of PCM is that you can never get any erroneous servo movements, however, the speed with which the signal is decoded and sent to the servos is very slightly delayed due to having to be processed in the receiver's decoder. To get right to your specific question, an FM set will work just fine for what you want, and though I use PCM, I would not hesitate to fly am FM system. SamTurner

FM is generally "stepless," so it does have _potentially_ greater resolution and generally better speed due to no decoding needed. BUT the control over that resolution is much better with PCM. And frankly EITHER system can have the control system resolution, torque and speed seriously compromised by misuse of the programs and poor hookups.

PCM, which is also broadcast on an FM carrier, has more resolution than you need and plenty of speed also (modern systems that is - 1024 resolution and very fast. Early systems were not as good and some still think of PCM as slow and chunky, which is no longer the case). The advantage in my opinion (and I ONLY use PCM) is the way they react to interference. Either will probably hit the ground if some dweeb on your channel turns on and stays on while you're flying. But PCM will "hold" thru the vast majority of momentary hits (most common type of interference) and you'll never know they happened. FM will happily respnond to any signal on channel, whether from your TX or some (any) other source.

Also, you can set a failsafe in PCM to - for instance - put wheels up and chop throttle if signal is lost. (Unlike Evan I like to have the gear retracted for off-field landings, but that's strictly a personal preference.)

If you use Futaba, (I don't) the best buy is the 8UAP. Not only is it PCM but it comes with much better servos, which actually make up most of the difference in price copmpared to the FM version. And the radio has about 95% of the features you'll ever actually want to use at about 35%-40% of the cost as compared to the 9ZAW. Eric Hawkinson

The biggest difference between PCM and FM is that FM allows you to crash your airplane yourself, while PCM will sometimes do it for you. If local flying is all you're going to do, go FM and don't sweat it. Any interference that lasts long enough to make your airplane crash in FM will probably last long enough to make it crash in PCM as well. Fail safe can keep your airplane in the air long enough for you to possibly regain control, so long as you don't run out of fuel. If your fail safe isn't set up properly, however it can be worse than not having it at all, re: Gary Shaw's safety column in Model Aviation and the Sunday Fun column in RCM. Michael White

This is a fool proof method and works for any type retract not just the Supras. Take the Supras and measure the length of travel the control arm makes from fully retracted to fully extended. Usually about an inch and 1/8. Now, just measure the same distance on the round wheel (usually the second ring from the outside) and drill two opposite side holes. You've got it. Don Ramsey (Sam says the same thing below but says it a little better)

If you DO want to know EXACTLY how much throw to allow for with the servo output arms, there is a very simple method to determine the throw you need. Put one retract so it sits flat on a piece of paper. With the control arm pushed in fully, mark on the paper at the position of the hole in the control arm. Next, extend the control arm fully...again, mark the position of the hole on the paper. This gives the total throw required. Divide the distance in half, and the result is the distance of the desired hole in the servo arm from the center. Use just slightly less than this measurement or put a slight bend in the clevis rod going to the retract to allow for any error in your measurement. Always connect the clevis rod to the retract with a screw-type clevis which connects directly to the control arm....this lets you compensate for any error you incur while attaching to the servo. Sam Turner

Ever have a problem getting the backing off a piece of Monokote you just cut? Well, there's a simple way to get it done. Just take your exacto with a #11 blade, use the tip of the knife and on the backing side of the covering, slide the knife tip through the backing at an edge and pull it up. Use a sharp angle on the blade, pierce the backing and lift it.

New airplane...first flights...things are going well...UNTIL the pre-flight use of the ESV, which reveals a 5 cell battery pack reading 4.96....Hmm...so we fast charge, measures okay, off we go....Flights are fine. End of day....checking battery....reads 4.5 (remember this is a 5 cell pack !!)

At home, I find the battery pack has a shorted cell...reads 0.00 volts ...other cells fine. What's interesting about this???

Part of building the new plane was cycling the 1200 mah, 5 cell pack. Things were great. Charger fine, peaked and measured before flights today. LITERALLY, the cell died BETWEEN flights....

Why do I tell this? Had I been using a 4 cell pack, and one shorted, I would now be the proud owner of a brand new crash.

The lesson refreshed for me here...ALWAYS use the ESV. Pay attention to it. Make NO assumptions about packs that "checked fine yesterday"....had I done that, my NEW, and GREAT flying Hanson EMC2 would be a trash bag filler. And I'll likely NEVER run a 4 cell pack...remembering that NO receivers will work at 3.5 (which is what I WOULD have had with a shorted cell in a 4 cell pack, instead of the 5....). Instead, I'm off to the field tomorrow, with spare pack in hand....Enjoy your flying, folks. It sure is easy for Murphy to nail us all....

Here is something to chew on, I have always used monokote and sealed the surfaces. However, using CA hinges and attaching with no gap present, is it really necessary? The only real feature I see with a tight fit anyway is extra security if a hinge should fail...Michael Marohnic

Seal them anyway. Even gaps that appear nearly perfect, are not. When G-loaded, slight differences in the gaps will likely show up, causing a slight roll while pulling or pushing. I find it easier to seal the gaps, particularly aileron, and know that is done. Then concentrate on other reasons for unwanted roll such as rudder and thrust trim. Ron Lockhart.

Here is another choice --I use pinned Klett std and pull the mating surfaces togather with masking tape whilst they are drying (epoxy)--On the models I am presently using, I find no need to fuss with the Monokote seal --Years ago I found that it really helped on some -NOT ALL models –Dick Hanson

I agree with Ron, I too have been using the EZ type hinges but continue to seal the aileron and elevator gaps. Although I use Monokote on the flying surfaces I have been using clear Ultracote to seal the gaps. Keeps my trim scheme intact and Ultracotes lower tack temperate ensures my Monokote job is not disturbed. I find with low temps I can peel the Ultracote off the Monokote should the clear Ultracote develope a split making replacement a snap. I used to use the clear Dave Brown sealing material and found it stuck well to painted surfaces but I had trouble keeping it down on Monokote. Ed Miller.

I use clear silicon to seal the gaps. This is the stuff you buy in a hardware store for sealing seams around bathtubs. I make a 'trowel' out of 3/16 balsa that matches the angle of the bevel between the aileron and the wing trailing edge when the aileron is fully deflected. Be sure to release the pushrod from the control horn. Working from one end of the aileron from the bottom of the wing, work in as small a bead of silicon as possible into the gap. The less the better to eliminate any binding. When you are finished, check the top side of the wing to make sure you don't have lumps in the top seam. If it is uneven, simply use your 'trowel' to eliminate the uneveness. When you are finished, reattach the pushrod and set the aileron in the neutral position for drying overnight. You now have a sealed gap that is practically invisible with no binding. An added benefit is that the aileron, or elevator or rudder, will always want to return to neutral. I have been using this technique for years without any problems. Rich Fletcher

I did a bit in the K-Factor a few years back. Still works great and still using the same technique as follows:

The end result is much lighter because the hairspray limits the penetration of the epoxy to the wood. You'll see what I mean the first time you try it. If you're worried about the strength, don't be. Von Linsowe's TOC 202 was done this way and probably had more stress put on the structure than most of us are capable of short of crashing! Verne Koester

I do the same sorta process but use BALSARITE. This cuts the amount of epoxy I used per sheet by about 40-50 percent. I also think I get a better bond because the glue ends up between the foam and wood, not soaked in to the wood. One point I would add is to sand the foam itself with 240 grit, then vacuum. Gene Maurice NSRCA 877 (Editor's note: insure the balsarite is completely dry before putting on or near the foam because the solvents will melt your cores).

The Balsarite method works terrific and as a real bonus, makes the wood fibers of the sheeting significantly stronger than plain / bare / untreated wood -- not to mention the reduced amount of epoxy required to properly sheet the core. Be sure to let the Balsarite dry completely (20 - 30 min.) before initiating your sheeting procedures -- it contains solvents that must flash off. Michael Onstott

I Cut the servo box in the foam before I sheet the wings. With the core lying in the top shuck I reach threw the servo cut out and mark the exit location on the shuck as well as the entrance location at the root. After I sheet the wings I lay the top shuck on the table. I use a simple jig to guide an aluminum arrow shaft with a standard point. The jig has guides that are adjustable for height at both ends. Align the shuck with the arrow about 1/8 from the shuck on your mark and tape the shuck to the table. Put the wing in the shuck with a little weight on it. Heat the arrow tip with a torch and plug it in. The jig is Simple to build (maybe fifteen minutes). I took a piece of 1/2 " hardwood 8" long and drilled two pins into it so it could be removed and installed on the table. Then I used four pieces of lite ply for the guides one set with oblong holes mounted on the ends of the 1/2" hardwood and the other drilled for the arrow screwed on with oblong screw holes to allow adjustment. It never misses and is handy especially if you have a bunch of the same wings to do. Harold Collins

I have a router fixture for my Dremel tool which really makes this process easy. First I use a 1/8" bit a rout a channel 1/4" deep from the servo bay to the root. This is followed by routing a square "tube" into the foam using a 3/8" x 5/8" Dremel grinding stone, letting the shank travel trough the channel. Takes about two minutes, NO chance of getting out of line, and results in a very smooth interior surface.

The best way I have found is neat and clean. Get a Weller soldering gun and make a "loop" that is about 1/2" in diameter with the wire extending straight up at the same place. These wires attach to the soldering gun. The wires going up cannot touch or the heat will build there instead of the entire copper wire. Then attach a couple pieces of wood to the loop as a stop so your depth is the same along the length of the cut. The key is to make the extending wires in the same plane so that when you cut the holes they track in the slot left. Now tape a straight edge to the wing surface and use it as a guide. The circle loop will leave a great hole for servo wires and requires no other clean up. Just take your time and make the bend the loop around a dowel and then you will have a round hole. Looking at the loop flat it should look like a wire circle with a wire sticking out he top. (i.e. Thermometer shape) Looking at the edge it should have a slight offset as the wire "spirals" to get the offset. The wood pieces are screwed together to clamp the wires in place and provide a stop. Works very very well...This will leave a small as in 1/8" trench in the top or bottom of the wing but will not be a factor in sheeting or strength.

Now if the wings are sheeted then use a brass tube, works good in a cordless hand drill.

Those who have a variable power supply, can make a small thin wire cutter --shaped like a tiny light bulb--with the neck of the cutter twisted 90 degrees - this will drop thru the foam surface and cut a round hole --the size and shape of the "bulb" portion--leaving a tiny slit in the wing surface --which causes no strength problem. when the cut is completed - a nice round rod of foam can be pulled from the core- -the resultant surface is smooth and firm-- allowing the servo wires to easily slide thru- -Sorry -no high tech stuff needed . Dick Hanson

August 2014: OK fellas: I have found the answer to those who say it is too expensive to enter pattern!!!!!!!!!!!!!!!!!

I just flew the e-flight Splendor and it was great. At $199 for a model with motor, ESC, all the servos and receiver, its hard to beat. The setup was the stock plane with all stock serovs, a Futaba receiver, and 4000mah 6S battery.

We changed the receiver for a Futaba one, set the aileron throw to 9 degrees the elevator to 10 and a lot of rudder. For normal pattern flying the ailerons were a little hot so on second flight they were reduced somewhat. Third flight, I flew the new Advanced sequence using about 60% of a 4000mah 6S battery. There was little wind, but in that condition, the model could be very competitive in Advanced. Since there was not much wind I�m not sure how it would do in the wind but it is a great plane for not much money.

Oct 2008: I highly recommend the Vanquish. Extreme Flight RC sells this fantastic small, fully capable pattern plane. Also the wings are removable and RC Aerobatics.com has some very nice small wing bags that work well for the Vanquish. Regards, Bryan Kenedy

- All my Bolly pipes are 7/8". The Bolly mufflers (480R and 590R) have a 3/4" flange for about an inch and then a 7/8 flange beyond
- Macs headers are 7/8"
- ES pipes I've seen are 3/4 for the 2-stroke pipes. 5/8" for the 4 stroke pipes
- Karl Mueller headers are 3/4"

From Lance Van Nostrand

Building	Flying
Weight of Components	Flying and Judging Snaps - Dave Lockhart
Elevator Control Systems by Troy Newman	Double Immelmann / Spins / Snaps
Control Horns/Hatch Mount/Honeycombing	Using the Rudder
Drilling Aileron Lead Holes	Battery Chargers and Charging
Engine Mounts - Vibra Damp, Hyde & Hanson Rotr-Mount	Battery Clinic - Red Scholefield
Gap Sealing	Entry Level Airplane (Aug 2014)
Monokote Tip	General Thoughts - Mike Harrison
Mounting a Chin Cowl	No Coach - Bob Pastorello
Mounting a Nose Ring	PCM vs FM
Rebuilding Fibreglass Fuselage	Why Use a Battery Checker - Pastorello
Retracts-Installing	Upgrade Servos
Teflon Header/Pipe Connector	Flying in Wind - Don Szczur
Wing Sheeting	2006 NATS F3A Unkown Sequences
Header and Pipe Sizes	Triangulation Trimming - Bryan Hebert (Jan 2010)
Making a Clear Canopy	Trimming with Bryan Hebert (April 2014)
Building the PL Products Partner - Earl Haury	Engines
Fitting a Canopy/Chin Cowl	Maintaining and Running YS Engines
Pushrods, Servos and Control Linkages - Troy Newman (PDF file)	Working with OS 140, etc
Wheel Pant Mounting - Wayne Galligan	Webra Engines
Airplane Caddy - Feb 2013 (PDF file for easy printing)	YS Engines - Troy Newman Pattern Talk (Excellent) (Jul 2009)
Pull-Pull Exit Holes - July 2013 (PDF file for easy printing)
About Balsa - NEW!
Balsa Weights in Ounces and Grams (pdf file) NEW!
Calculating Required Servo Torque NEW!
Glue - Bob Smith guide on Glue NEW!
Painting - All you wanted to know

Making Tube Sockets - NEW! May 2014 (PDF file for easy printing)