Aerotow Trainer Sailplanes

[ARUP]

I toyed with the idea of a wheel and spoilers but decided to KISS! I'm keeping the rubber band-on wing just in case of a ground loop at take-off. I fully sheeted the 'D' tube. I reduced the dihedral in the main joiner. There is ample material in the kit for this. Way to go Sig! I love Sig! One sailplane has kit wing plan form which is double taper and the other has a straight LE root to tip. The first one with the double taper has a little built in wash out. The one with the straight LE shouldn't need it. I just laminated a bunch of spar joiner 1/64" strips to 'fit the bend' of the spars for the straight LE one if that makes sense.

The H9 Ultra Stick will have more than enough vitamins to pull the Riser!

[Joespeeder]

Funny John, I just heard that the new group of sailplaner's in Frankenmuth bought a bunch (10-12 I think) of Sig Risers from the LHS and are doing a group build this winter ! This truly was a result of the aerotow event we started 2 years ago and they fun they had on the foam Ka8's. Fun to see a bunch of sport plane guys enjoy a little slower pace and all they have to offer. Keep us posted.

Joe

[jswain]

What a great idea !!!

Not that its earthshaking but that it is a basic and quick (relatively) aerotowing solution to fun fly sailplanes or introduce existing flyers to something *non-competitive* oriented.

After seeing this thread i ordered a sig riser 100 kit and will make the modifications to have a tow release, ailerons, spoilers, undo the balanced rudder,
and round out the flying surface's tips just as seen above. Got to have the fixed wheel too - just have to........

To tow this Riser 100 locally ( and my just finished 1/4 scale hall cherokee) i have assembled all the bits and pieces to complete a stock H9 81" Ultra Stick.

No doubt i will take it to regular aerotows in 2019 with a buddy box for others to try.

john s. in so. calif.

[ARUP]

Thanks, Jim! I have a bunch of these so when they get all busted up I'll replace them with the ones you mentioned. I plan to bring the extra 55s with me during any outings just for that purpose!!! I don't know how I ended up with so many of these 'Feathers'! Must have ten more in a box besides the ones I'm using for these two birds

[JimD]

Mike, when we were using the Easy Glider trainer, we found the HS-55 servos were plenty strong enough for the flight loads, but not the abuse of the landings (cartwheels, tree branches, etc.). They were replaced with HS-65HB servos and no more problems!!!

[ARUP]

If they survive I'll bring 'em to Frankenmuth next year! That was fun!

[ARUP]

They are 2 meter airplanes. We'll try 'em out and see what happens! The tow plane is powered by an Enya 40 2 stroke that has a baffled piston so not a lot of power there!

[Mark9]

Mike, I agree with Victor. Many of the early thermal ships had a balanced rudder and they were quite prone to flutter, even at normal flight loads. Eliminating the aerodynamic balance is one mod most do to eliminate the problem. Word is that the servos at the time were to weak and needed the help. Also, talking servo power the HS-55 is pretty small and may not be up to the task. Are they 100" or 2 meter? If they are the 100"er I would go with stronger servos on both flight functions the nose weight will be required anyway. Let us know how it goes. Great idea to get people involved.

[Joespeeder]

Hi Mike,

Cool project !

Thanks for the shout out. We've found trainer aerotow sailplanes very fun and interesting. Some things you'd expect and lots of surprises in getting lots of aerotow 1st timers into the air for their first tow.

Thanks to the Ka8's, we had 2 sport pilots that added balsa sailplanes to their fleet of rc aircraft for last years event. I know we generated interest in some of the DLG guys and I'm betting some will add an aerotow plane to their lineup from the exposure they got to aerotow at the event.

Plus, thanks to our event the Frankenmuth Aeromodelers have generated lots of interest in sailplanes in general and now are flying sailplanes on Wednesday mornings.

They have a group of guys that are learning to thermal and really enjoying the change from power. Electrics and winch launch mainly but if I could get up there I'm sure we'd do aerotow as needed.

I'm really a carpet bagger up there. They are very kind and excited to see the aerotow event grow each year.

Keep us updated on your progress and how the trainer works out.

Joe

[ARUP]

Thanks for your concern! Hopefully, high speed towing will not be done so we can only hope flutter won't be an issue! The kit is designed with a rudder like this. I merely rounder the corners. At least the loads on the Hitec-55 'Feather' servo will be reduced. Hard points were added to the fin and stab so they can all be braced together in case a hard landing causes the fin to break loose. It is poorly designed IMHO. I 'doweled' the fin's LE to the bottom edge that is glued to the stab and have some large-ish gussets in there. Flight testing will commence as soon as nice weather arrives. It rained all weekend.

[edfmaniac]

Easy Glider is a great trainer and solid performer in light lift. I like those Risers too. Might take the air balance section of the rudder off though, or beef it up to prevent flutter on tow.

[JimD]

Absolutely great idea Mike. We did this back in 2010-2011 with an Easy Glider and a Telemaster 40 powered with an OS .52 4-stroke glow engine. Dozens and dozens of pilots had their first aerotow experience with it.

[ARUP]

Two Sig 'Riser' sailplane kits are being modified as aerotow trainers. Construction of the air frame is done with one. So far, it weighs 705g with two regulators, four Hitec 55 'Feather' servos, receiver battery and JR DS368 release servo. The fuselage of the second is finished. The other will get completed as soon as the first proves airworthy enough! The wings were 'straightened out' in lieu of the polyhedral design and strip ailerons were fashioned from the kit's TE. A retracting 'pin-in-slot' release was built into the nose. The tail feathers and wing tips were rounded... just for fun... and the rudder has pull-pull control. Spoilers were contemplated then dismissed because I wanted these to be very simple flyers... and I was lazy! Hopefully some interest will be generated when the 40 glow trainer tow plane and these are brought to the field and flights offered.





Thanks to Joespeeder in Michigan for the idea! He had a couple of small sailplanes for folks to try out at Frankenmuth. Wish me luck!