Tiny Gliders Postal 2009

Alexandre Cruz has created a fabulous blog for the Tiny Gliders postal event this year. Please do enjoy building some 6" and 8" gliders and fly in it. It's a lot of fun and easy to join in! It would make a great club event too, or activity for the kids. There's no excuse....

Left, a photo of my 6" DOGEAR hlg.

Thanks Alexandre!

P-51D Mustang - Completed model

Here she is, complete with pilot. One thing I learn from this is to never, I repeat, NEVER, use domestic tissue again. Japanese is so much better. This stuff shrinks in weird ways, is not easy to apply and the finish is lousy.


I love the lines of that wacky Dick Baxter prop - which is pretty much as per plan. I used a yoghurt pot rather than a coffee cup.







Weight without rubber was 8.8g. Prop on its own weighed 1.8g. Here is a photo of two prop centre shafts. The top is a ramp type of freewheel clutch, the bottom has a Garami-style latch. They're both smooth, but the ramp is more compact so I used it because of the spinner. Spinner was made out of tissue pva'd to paper. Cut out a semi-circle and made a cone out of that.




Power is one 1/8" loop. So far, I've only given her ~150 turns. Stab adjustment was required, but no ballast at all (thus far). All indications are that she's a good flyer! Need a good day to try her out properly.


A very enjoyable build.

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!