Tandem rotor gyroplane

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joe nelson

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Joined
Jan 9, 2008
Messages
265
Location
Cincinnati,Ohio
Ken, It isn't full scale yet. It is about 40% scale and I choose this size because of the problems with the first models. I found the the rotor blades in the first models acted differently from a full scale gyro. It took me a year and a half to find this out. I found that the blade reflex on models needs to have a down reflex. I think it's due to the rigidity of the blade longitudinally. Small models have light weight balsa or basswood blades. When rotating it noses up in the relative wind and needs a down reflex at the trailing edge to compensate. I'm hoping that the 40% scale I can use a more rigid material in the blades to see if my hypothesis is correct.

I certainly appreciate your kind offer to machine some of the parts and I may take you up on it. I'll need to cast more parts before committing to any help. I need to calculate the metal shrinkage for my parts which has come out smaller than the needed parts.
 

Blue Chips

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Joined
Oct 15, 2014
Messages
370
Location
Mount Gilead Ohio, USA
Ah, I had misread your post all on my own and should have not misinterpreted 4X as full scale after having read your post to date. Sometimes I amaze myself how the obvious can be overlooked.


Offer to help in machining stands, if/when you may require that.

Ken
 

joe r nelson

Member
Joined
Nov 8, 2019
Messages
5
Well folks, I'm still alive and trying to recover from my severe back injury which has kept me from doing much at all. I am sitting here reviewing my thoughts from over the last few years. I realize that I still love this tandem project and fully intend to keep it alive. In the next few days, I will be venturing down into my shop to inventory the project. I will update you all with the status of tandem.
 

D Hillberg

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Joined
Nov 23, 2010
Messages
1,262
Location
very low low low earth orbit
Bad back too. Broke mine into retirement. Might limit what goes but it still goes...

balsa is flexing with the lifting moment try adding a penny on the tip [get centrifical twisting moment to stop twist up]
 

joe r nelson

Member
Joined
Nov 8, 2019
Messages
5
You can't leave us hanging with that.......
sorry, I didn't mean to do or leave anyone hanging. The doctors had to correct an earlier fusion which didn't go well. I was unable to walk and it had nerve involvement which caused me to be incontinent. I am not accustom to wearing diapers or peeing in a jug. When I was able to use the laptop again the website had required me to reregister. Please understand no hanging was intended.
 

joe r nelson

Member
Joined
Nov 8, 2019
Messages
5
Bad back too. Broke mine into retirement. Might limit what goes but it still goes...

balsa is flexing with the lifting moment try adding a penny on the tip [get centrifical twisting moment to stop twist up]
Have you worked anymore on the Mac tandem?
 

D Hillberg

Well-Known Member
Joined
Nov 23, 2010
Messages
1,262
Location
very low low low earth orbit
Mac tandem????

I do have a design laid out for an 8 place 'mini Chinook'.....

Got 3 other projects going, 1/2 scale AH 1 cobra, Sky Shark, Coanda fan fin, medical deck for R44 or R66 helicopters
 

joe r nelson

Member
Joined
Nov 8, 2019
Messages
5
Good to see you back Joe. It's been a long time. I hope to see further work on the tandem gyro soon. In the meant time, I wish you and all other followers of this thread, a very happy and safe Christmas.
Doug, Things are moving slowly and I have to find my notes and brush off the dust. Today, I was looking at my main problem, as I remember it, the gear boxes. I've tried two types and both required many pounds of torque to turn them. This is a bad thing for gyros that depend on free wheeling to spin-up the rotors. If I can't reduce the gearbox torque, I will have to go to using partial power or a pre-rotator. All of this adds weight.

Turd, I wished it end of the fusion thing but it is a on-going condition. The really bad thing is the medication needed just to function. At my age any change is difficult and takes a long time to overcome.

I would also like to wish all a warm and wonderful holiday to all my fellow Rotor-heads and everyone on the website. God bless you all!
 

joe r nelson

Member
Joined
Nov 8, 2019
Messages
5
Today, I placed an order for three books on 3d printing. I like the idea of producing parts as I need them.

If anyone has any thoughts let me know.
 
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