Free Flight Postals

Postal events allow competition without the formality of a meet. Each modeller sends in scores by a certain deadline, usually a series of times. Many are run on an honour basis - and I certainly don't know anyone who'd cheat by sending in false times - what's the point? In any case, weather conditions are not the same for everyone. So in my view, postals should not be thought of as "real" competitions.

Click here for a super list of some free flight postals. I was sad to see that the 2008 Tiny Gliders Postal had few entries because it is one of my favourites. The plus side is that Alexandre Cruz did a great job of keeping it going and there is good reason to anticipate that it will be bigger and better in 2009! If I find out the new website for it, I'll post it here.

Finally, how on earth did this patent get granted by the US Patent Office in 1975? There's no way it was novel or inventive at that time!

Catapult launched glider: Sotich 8" CLG

This is a catapult glider design by Charlie Sotich. It's a quick n easy build and flies reasonably well. The plan is available from the Aeromaniacs site here (click on the pdf symbol next to Catapult!).

This one took me just over half an hour to make and came in at 2.7g including nose weight. Not bad for an 8" span model. She flew right off the board with an in built left turn. First flight was a promising 36s in cold weather, 8mph wind.

Alas, after about a dozen flights, I pulled the elastic back too enthusastically and shredded the right wing - the curse of small CLGs! I'm oddly pleased because it was the wood that failed, not the glue joint.

Great fun while she lasted.

All was not lost, as I decided re-utilise the fuselage for another, different, wing and see what I could learn from that






So here she is the next day with a conventional 3 panel wing made out of 1/8 balsa. Also now sporting carbon fibre tow on the sides to keep the fuselage stiff. Weight has gone up to 4.2g, but she still flies well. Polyhedral is 1 3/8" under each tip. Too much, because she Dutch wobbles in flight, but at least showed no tendency to spiral in.







Here's a photo of the underside. You can see the Al-foil tape that I've used to reinforce the wing-fuselage joint. So far, no more shredding!

I think the original is prettier. The modified version seems more consistent. Best flight today was just under 45 s in winter conditions, with no flights under 30 s.

Rapier Rocket Car / Test Rig

Just got my sticky mitts on some Rapier rockets. I've always wanted to make a rocket-powered glider. Another project for next year...

I've never used these rockets before, so I built a test rig for my son. OK, it's a car, but the spoiler counts as a wing!  Inserted a stick-like fuse into the hole at the rear, lit it and then watched it fizzle out. Left it for a while, then tried again. Eventually, it ignited and whizzed off leaving a satisfying trail of smoke. I must get an electric igniter. It has a hot tip: insert in the hole to start the rocket. 

Model Glider Plans

If you're looking for really interesting A/2 glider plans, then the January 2007 issue of New Clarion is a great resource. It contains fabulous information on a number of, shall we say, "nostalgic" glider designs. A/2 gliders are basically the big ones - usually between 60 and 79 inch span (~ 2m). SAM 1066 is a UK based chapter of the Society of Antique Modellers - well worth a visit and their membership is free!

Converting a free flight glider to radio control RC

Free Flight gliders could be useful starting points for an RC conversion - to make a really high performance radio control glider. To flesh this out, here's an example of enlarging a Keil Kraft Soarer and converting it to RC (discussed on the RC Groups forum) :


And here's a super example of an RC conversion of the Lulu (50" free flight glider, discussed on the SFA forum, by my friend Eagleone):


I would suggest that neither the Soarer nor the Lulu is in the same league as the big A/2 gliders. Indeed, I daresay that converting one of those "biggy" free flight A/2 designs to RC would create a very high performance radio control sailplane.

If only I had the time to try it....

A Story about Pre-Flight Checks

Had to take a break from building the P-51D - birthdays, family stuff and such. In the meantime, here's a little tale.

When flying radio control, I try to be diligent about pre-flight checks. However, a month or so ago, I came a cropper while flying the STARLITE (see photos).

Picture this: after changing the prop and replacing the battery with a more powerful plant, she was flying beautifully, save for a noisy (definitely broken) rudder servo. I replaced the servo, and while testing on the dining room table, was delighted that the rudder operated as quietly as the elevator. Charged her up and excitedly, went off to the field. Did my checks and launched from a throw. She climbed a bit then - spiral dived to the ground! I checked rudder centre trim setting, it seemed ok, so I launched again.

Painfully, she spiraled in once more, this time losing a leg and a suffering a bit of minor damage to the fuselage.

What to do? I checked alignment of all surfaces. Nothing except an ever so slight warp on the rudder. Surely the spiralling could not be from that? With the plane pointing ahead of me, I waggled the stick.

Then I saw it. The rudder was moving in the wrong sense! I had done my checks the first time with the plane pointing towards me (and without engaging my brain!). It took 5 seconds to reverse the new servo from the TX switch, after which she flew beautifully (although now with one leg - fine practice for holding off on landings!). When I first heard the story of the pilot who chucked his radio control glider off a ridge, only to realise he hadn't turned the receiver on and then watched it fly off into the distance out of sight, I used to wonder "how could that happen?". Now I understand! For me, repairs were cheap and easy but I hope the valuable lessons learned last forever:

- Always take care over pre-flight checks. Do them PROPERLY, especially when excited about the flight.

- Never assume that a replacement servo operates in the same direction as the previous one. Check it!

P-51D Mustang - Fuselage and tissue covering

For some strange reason, I chose to use normal domestic tissue instead of the usual (and better) Japanse Esaki. This was white stuff from the local newsagent shop, pre-shrunk with water. This is my first effort at colouring tissue. Here, I'm using some very old art charcoal that's been lying around at home for over 15 years! You can also use coloured chalk. Loads of colours and tints are possible.

Simply rub it on, then wipe about in circles with a soft tissue until it's evenly shaded. I did both sides. In the photo, a strip of the original white tissue is on the left and a gey coloured piece for the wing is on the right.

I am not an expert builder, but I enjoy it and do take pride in my work. Below, fuselage sides going down. I'm building both at the same time (this is NOT the same thing as the second one over the first!). Don't bother with cling film between them - you can separate with a razor blade afterwards.














Assembling box fuselages can be tricky and fiddly. Cardboard formers - lightly tacked in place with CA glue - are tremendously helpful. Generally, I use woodwork PVA for all balsa joints and avoid CA except for the places where it's really advantageous, like for the formers here. The photo below is just before the sides were "cracked" to bring the back ends together.




Another view of the fuselage assembly and card formers. They are from a pizza box.












Here are the wings glued up and setting at the correct dihedral angle. This newsagents shop tissue is nowhere near as easy to work with as Japanese Esaki. It does make a change to use a material with a different texture though. The grey colour is just what I wanted - simulating the metal of the full-size. I will have to lightly dope it, to fix the charcoal in the tissue. Note the slightly graded colouring on the fuselage side - the top is grey while the bottom is white. I wouldn't have the patience to build proper scale models, and chapeau to folks who do. Sports-scale is good fun though - it's like a nod and a wink to the original full-size shape.

P-51D Mustang - Sport Scale Rubber Model

The P-51D Mustang is a very popular model aeroplane subject - and for good reason. The sight and sound of one in flight is just as iconic and neck-tingling as the Spitfire. The P-51D is recognisable by its teardrop bubble canopy, fin gusset (although not every D model has one) and distinctive "kink" in the wing LE near the root.

www.mustangsmustangs.com is a superb resource for information on these amazing planes. They served in air forces all over the world.

For some time, I've been wanting to build Dick Baxter's 14.5" sport scale rubber power design, plans for which are available at SFA. You can see the relationship of this design to his Akro model. It's a fairly simple to build rubber model that can be flown outdoors or with care indoors. All you really need are some 1/16" square spars, a bit of 1/16 sheet and a 1/8 square spar. Clearly, he has tried to avoid tricky building and curves while at the same time, creating a fair impression of the full-size plane. It seems like a well thought out design.


I started off with the canopy. This is the first time I've ever tried to hot-stretch canopies out of discarded packaging plastic. It's great fun!

Airframe is fairly easy to build, though a bit fiddly. Here are the wings.

More pictures to follow.