Another attempt,back-pack helicopter

[Sita]

Hello Dave,
that malady is called "Spendyonitis" (spend money because we have it,sometimes even when we dont have it,on things we dont really need to fall in the grace of others or to be "part of it")

Yes,that flip up seat and skids becomes attractive....over the years."Older" people like myself appreciate more the comfort of a hotel room over the excitement of a tent. This doesn't mean of course that there is no future in the developement of camping gear !!!! LOL !!

A single blade interleaving rotor system would be top notch !!!!

Yes, further information about Franz' electric project would be interesting Dave,thanks !!

Cita

[Sita]

Here a picture of how I intend to start my engine.Kinda like a "hillbilly" approach to some of you but I've used a similar system in the past and it worked OK.
No,I'm not going to use a string to transmit the power but for me it's the best way to determine the lenght of the required V belt.
Once the engine runs,the starter is easily removed from the airframe.
With the "half legs", it's much easier to work on this "thing".

[All_In]

Hi Cita

Very creative solution!!!

[Sita]

Originally Posted by All_In

Hi Cita

Very creative solution!!!

John,

poverty stimulates creativity....so they say LOL !!!
I would prefer a brand new engine with built in starter any time over the hassle I need to go through to get that thing running but so far it's still fun so it's OK I guess.Hope I can get the engine running again after some 15-20 years of complete silence !!

thanks for the kind words John,it's appreciated

Cita

[All_In]

Cita you know what I like!

That you are DOING IT!!!!

Very impressive all by itself and says a lot about you to me!

[Rotor Rooter]

Cita,

Your craft is looking good and you are probably approaching that point where outside purchases are required, such as rotor blades. You have also mentioned your hesitancy about putting much money into this hobby.

We both seek a low-cost and extremely light rotorcraft so the following may be of interest.


Just after Pascal's electric helicopter flight, a German group came out with their 16-propeller electric multicopter.
World's first manned flight with an electric multicopter - YouTube

Pascal started to consider the possible advantages of a mulicopter and I argued for the efficiency of two larger rotors. There were enjoyable discussions but then we moved on.

I am now beginning to think that the Quadrotor may play a dominant role in the future for 'in-flight' activities when the craft must have Vertical TakeOff & Landing capabilities. Of course these will be pilotless craft, but this does not preclude the advantages of the Quadrotor configuration for recreational rotorcraft.


This posting is getting long so to get back to your craft; what about considering the use of four 2-blade, perhaps wooden, propellers. These are a couple of pages that I am currently working up;

OTHER: Helicopter - Inside - Quadrotor - Electrotor-SloMo
DESIGN: Electrotor-SloMo ~ Frame - Quad - General
It can be seen that the HP requirements and the disk-loading per square foot are significantly different to those of Schoeffmann's craft.

My objective is for an electric craft, But, a lighter version of the Aerotechnik WG.21 rotorhead might be what will best serve your engine driven backpack. Also, the frame on the "Frame-Quad-General" above is designed for non-teetering weight-shift control.

Just something for you to ponder, if you wish.

Dave

[Sita]

Hello Dave,

I know it look's "almost complete" but that's a misleading idea.There's still heaps to do before them rotors will be spinning !!!

The thin line between "hesitancy to put much money into the hobby" and the "availability of money to put into the hobby" is sometimes hard to detect LOL !!!

I think that multi rotor systems are feasable "only" by the use of power sources small enough to place close or on the rotor axis'.....as in electric.
As my "project" stands today it probably wouldn't be too difficult to implement a multi rotor concept but my main concern would be how to transfer power to the seperate rotors....without a "massive" gain in weight?
If I would have the ability to go for electric power than I probably would "choose" something like the quadrotor but having one "heavy" reciprocating engine scares me away of dealing with power transfer to the rotors.
Even this simple little project is building up weight faster than I ever could imagine !!!!!

Maybe later Dave.....who knows !!

Cita

[Rotor Rooter]

Hi Cita,

All that you say makes sense; and your desire is for a large diameter teetering coaxial.

A heavy craft with pilot may not fly, but you can still operationally experiment with it while you stand on the ground and it is well tethered to disallow any accident. Over time this may allow you to make improvements and reduce weight. Perhaps eventually flown remotely as a very large RC.

You've got to keep working on it.


I am going to take a little time to look at putting the weight-shift linkage, which was worked out for the Quad, into the roll portion of a Side-by-side.

IMHO, there is a bright future for a VTOL craft that can compete in the price range of the gyrocopter. Perhaps the near-term answer is to substitute a lightweight genset and capacitor for the eventual battery.


Dave

[Arnie Madsen]

Your machine is Looking good Cita

I came across this video .... not a backpack helicopter .... thought your readers might find it interesting anyway.

(Maybe Russian) and I cannot translate. Looks like a couple of airfoils under the prop-rotors for control ... but appears he is having control problems.

http://www.youtube.com/watch?feature...&v=-zIulWZCiQw

[Sita]

Hello Arnie,

thanks for the kudo's and the Polish video.
Yes,I've seen this guys video's before and he's progressing on a steady pass.
I allways wonder why these people spend so much effort, and possibly money,when they could build a tripod like the Schöfmann helicopter for a fraction of that.My opinion is not strictly objective as I'm a big fan of Mr. Schöfmann so it should be regarded as such.
I guess everyone has his own valid reasons for building the things they do,just like I try to convince myself that the tripod helicopter is the right thing for me.
He changed from a side-by-side configuration to a co-axial and I would like to know the reason for that but it seems a bit difficult to get in contact with that guy (I've tried without succes). The side-by-side concept should be more effcient but perhaps compactness is more important to him,I don't know.

We're "pondering on" Arnie in the hope to ever reach a fraction of the "succes" of Mr. Schöfmann !!

Thanks,
Cita

[Rotor Rooter]

Cita, I ask Hans on Friday if he had spoken with Franz recently. He said that he hadn't and there was no mention of phoning him. From the previous conversation they had, it was speculated that the electrics, the cost of batteries, and last but not least age, might be deterring Franz.


Dave

[StanFoster]

Cita- I am always checking in on this thread. I find it fascinating the obstacles you slowly are overcoming as you develop your backpack helicopter. Thanks for posting your project that has to be very satisfying to you as you make progress.

Stan

[Sita]

hello Dave,

thanks for taking the trouble to gather info about Franz' electric helicopter.
He must be in his early seventies now so I can imagine that this can be influencial on the speed of work.

Hello Stan,
thanks for the encouragement,it's appreciated.
I would be a big liar if I told that this is my most preferable way of working on this developement but it is the way it is.
Perhaps there's a "benefit" if the thing ever is a "succes" and that is the knowledge that it was done with very limited means.
I wish I could just order the things I think I need Stan instead of trying to find a way to scratch build a substitute that cost "nothing".
Honesty must have it's place so yes,it's encouraging and flattering that people appreciate the work you do even if it's not proffesional or done the way it should/could be done.

Thanks,
Cita

[StanFoster]

Cita- I would place more value on the stuff you made with your brain controlled hands instead of a wallet controlled order over the phone. I think that is way cool making most of your parts. I get far more enjoymewnt making something than ordering it, but since I am not a machinist, i have to order most stuff. Your project just fascinates me. Stan

[Sita]

Thanks Stan,

as long as people show interest in my pictures/progress I'll try to keep the images following till I finally hope to show a little video of me, hopping around in it.

thanks again,

Cita