AirBike 103 Ultralight Update- Engine & Motor Mount

[@rcpilotguy5890]

Great job dag!! As you know I love my 340. You will love how good it runs. J-Bird is a great company!

[@dagtheaviator]

Thanks buddy!! You plane flies great with your 340. Rock ON!

[@Yogenh]

I hope that you show some of your flying and flying of your airbike

[@keithschneider6348]

340 should be nice and dependable.

[@Andrew-lk5ov]

Here is a Johnny-come-lately comment about your motor mount post. You had expressed some concern about the wall thickness of the mount post and had increased it for structure and peace of mind. I, too, think about crushing the square tubing or dimpling the sides when the mounting bolts are tightened. The Affordaplane engine mount is quite similar to the Airbike and used a piece of 2x2 delrin or nylon friction fit insert in the tube for added torsional stiffness and to keep the tubing from collapsing from over tightening the attachment bolts.

[@timmytheimpaler1750]

Can't wait to see the go pro videos

[@dagtheaviator]

Thanks!

[@noellwilson1273]

22:30 You comment about the 250 cc engine requiring added weight in the tail to get the CG right. I’m assuming that “CG” means in flight weight and balance. Reading the Jordan Lake Aero site, they now list the Hirth F33 which is a 312 cc, 28 lb, 28 HP single cylinder two-stroke plus “careful attention to weight” to make part 103. Does this “factory setup” require added weight in the tail? (I’m not asking about the difference between a 250 cc and a 312 cc engine. I’m asking if the factory plans plus weight and balance checks are going to require extra weight in the tail.)

[@dagtheaviator]

CG is the recommended "center of gravity" shown by the plane's designer. The 250cc engine was too light. So, I would have had to add weight to the nose. And adding weight to an already lower-powered engine set-up would have been silly to me. Now, the larger engines may make you nose heavy. Then you would need to add weight to the tail. The larger engines could push you over the part 103 254 pounds. At this time, I feel I will be at 247 pounds. Just low enough to be part 103. I hope this helps. :)

[@vupilot]

I'm curious about one thing, if there was a reason you have the vertical mount bolts in that orientation with the nuts on top? I always thought they taught to put the bolts in an orientation such that gravity would have a chance of keeping the bolt in place if the nut were to back off. I noticed your plans also showed the nuts on the bottom as well. Cool project!

[@dagtheaviator]

I have meant to flip them over. I had the motor mount on its back on my bench when I installed them. My bad. LOL. :) Rock ON!

[@matthewmoilanen787]

Don't listen to the armchair engineers that have absolutely no grasp of material properties and design. A KC 135 only uses 3 bolts to hold the engine on it. Aircraft in particular are designed to have flex so as to not fracture. By the way I'm a former aircraft Crew Chief in the Air Force and a designer/drafter currently. Just an odd spec, a fully loaded B 52 wingtip will move up 22 feet before takeoff to allow for this flexing!

[@ramaoramoscorrea5312]

Olá sou do Brasil e estou ficando muito entusiasmado com os seus vídeos explicando sobre a construção desse avião, tenho um sonho de construir um, mas,! Não consegui encontrar a planta do modelo para construção, você teria como me mandar uma sugestão de como e onde encontrar essa planta??

[@dagtheaviator]

www.jordanlakeaero.com/PlanSets.html

[@alfredoreyes26]

Why is the engine going backwards?

[@dagtheaviator]

Ultralight engines rotate at what ever direction the engine being used does. The engine I am using was in thousands of snowmobiles. Its just the way it turns. That's why when ordering a prop they ask what direction the prop is turning.

[@alfredoreyes26]

What ratio ratio do the pulleys have?

[@dagtheaviator]

2.67 to 1

[@alfredoreyes26]

How many hp does that engine have and maximum rpm, thank you

[@dagtheaviator]

around 30-32hp

[@tpspc03]

I think i would prefer solid rivets over the two bolts for the angle to square tube attachment. A matrix of rivet will have more bearing area. Those holes in the square tubing will elongate over time.

[@dagtheaviator]

Interesting, all the AirBikes are designed this way. And one of my pals has one that’s over 18 years old, and the holes never elongated.

[@cropduster48sady46]

There is nothing wrong with your motor mount design. You carry on just like your going. The only thing I see you doing later on is changing to a Used Rotax 503.. Much better designed engine internally.

[@rcpilotguy5890]

Since the 80's many have had great success with the 340. I have had two 340 and one 440 over the years.

[@ulbuilder]

​@@rcpilotguy5890I had two 440s, front crank bearing exploded on one, crankshaft snapped in half on the other. Some have success, some don't.