Propeller vs Direct drive

[Superfuelgero]

Originally Posted by jamesqf

So you're going to drive your ultralight around on the roads? But I'm still confused about the why part - unless of course you're planning to take the traditional meaining of IFR (I Follow Roads*) to its logical extreme.

I wasn't going to post these so the idea wouldn't distract the technical discussion. Looks like that's been fairly well covered, so now some fun:

http://http://pal-v.com/


Super Sky Cycle, The Flying Motorcycle | motorcycle News @ Top Speed


Meet Dezsö Molnár and His Flying GyroCycle - Tested


But I want to do it under 103. The prop idea was to reduce weigt to allow a 4 stroke.

Originally Posted by Ryland

That 59% is in ideal conditions as I understand it, the mathematical max that you can get before air just moves around the prop.

Hmm, interesting. Thanks.

[jamesqf]

Originally Posted by xntrx

But I want to do it under 103. The prop idea was to reduce weigt to allow a 4 stroke.

Now that's an even bigger why. I can, barely, see the point of a fixed-wing roadable ultralight - you might not have room to take of/land close to your destination - but with a helicopter? And with an autogyro, you still have to have a takeoff run.

And if you want it under FAR 103, remember you'll have to add weight for things that make it road legal, like head & tail lights, turn signals, etc.

[Superfuelgero]

Originally Posted by jamesqf

Now that's an even bigger why. I can, barely, see the point of a fixed-wing roadable ultralight - you might not have room to take of/land close to your destination - but with a helicopter? And with an autogyro, you still have to have a takeoff run.

2 strokes are just temperamental and more prone to failure. They're also less efficient overall, but very light in hp/lb.

And having it roadable allows me to find a spot to use for takeoff and landing. At home its not a problem the driveway alone 800 feet. Destinations are a problem. A Pre-rotor would help, and may provide a method of propulsion tying into that system (if hydraulic).

Originally Posted by jamesqf

And if you want it under FAR 103, remember you'll have to add weight for things that make it road legal, like head & tail lights, turn signals, etc.

No turn signals here. Will need a headlight, horn, tail/brake light, and one mirror. A gryo seems like the best option. A helicopter would be hard to make light enough, and a plane too bulky. If a 60 year old square tube Bensen can be under 254, an updated design with emergency gear allowances, some propulsion system and street gear should be doable.

[jamesqf]

Originally Posted by xntrx

And having it roadable allows me to find a spot to use for takeoff and landing. At home its not a problem the driveway alone 800 feet. Destinations are a problem.

So how far are you looking to travel on road at your destination?

My solution (with a Piper Cherokee) was to just take out the rear seat so I had room for the mountain bike. And would land on dry lakes, or the occasional stretch of deserted highway.

A gryo seems like the best option.

I honestly wouldn't think that would be at all practical, with the large rotor hanging out there where it can bang into things, or be hit by people not seeing it. Even if you could secure it fore and aft, it'd still be like carrying long pieces of material sticking out the back of your pickup. You really have to give some thought to Murphy's Law, you know :-)

But I do understand about not wanting 2-stroke power.

[RedDevil]

Bumped into this on the web:

An Aerosani (Aerosani - Wikipedia, the free encyclopedia)


which linked to The Propellor-Driven Sleigh. like this NKL-26 Russian military aerosled:


1932 Helicron (The Helica.):


Those last 2 and wagonloads more eye candy can be found in the Museum of Retro Technology

for example the Cyclogyro (http://www.aqpl43.dsl.pipex.com/MUSE.../cyclogyro.htm):


PS. saw Old Mechanic found that site first: http://ecomodder.com/forum/showthrea...gns-30553.html
But it is much more than just engine designs

[user removed]

I still like the idea of a 30-06 spitzer bullet shaped ducted fan. Very light weight and then you use the fan for higher speeds. Plenty of bikes engineered for higher speeds and relatively lightweight

If my 50 year old scooter can go 43 MPH and get easily over a hundred mpg then A bike with a modern engine would be interesting, just a small 4 stroke 50cc so it falls under scooter laws.

What appeals to me is at higher speeds where you can't pedal a normal bike the ducted fan would give you thrust assist, which could be supplemented with pedalling to get to a higher speed or climb a grade' the use the fan to maintain ahigher average speed than you could ever do pedalling.

Carrying an extra source of thrust also would reduce the aero drag, pulling air from high pressure areas and blasting it out in the rear in the normal low pressure area.

regards
mech

[gone-ot]

If you pardon the obvious PUN, some of those propellor-driven car ideas SUCK and others BLOW (wink,wink)!

[RedDevil]

Originally Posted by Old Tele man

If you pardon the obvious PUN, some of those propellor-driven car ideas SUCK and others BLOW (wink,wink)!

Either way has its fandom...

[niky]

Well, that's a new twist on the situation...

[redpoint5]

It looks like the engineers thought of everything on this design. They have smartly located the fuel tank in front so that when the aircraft crashes, killing everyone, they can be cremated on spot.