Panther Or These??

[Tom Wright 2]

Posted by wayne young on 08/02/2013 18:44:35:

Does anybody make an artf auto gyro would love to fly one but have to many models on the building board to take on another project..

Wayne

Have a look at THIS.

Tom.

[Tom Wright 2]

Hi Stephen.

Interesting ! It does looks as if the rotors are contra rotating .

Rich will probably recognise the model ,Its a bit like the Boddington but the top mounted, fixed head rotor set up looks interesting , are the blades solid or built up ?

Tom.

[Tom Wright 2]

RS.

I had not read back and seen the OPs reference made to CRP.Under these circumstances my off thread comment was not justified, so my apologies.

Tom.

[Richard Harris]

Stephen,

It is a David Boddington 'Gyrace'

Rich

[Richard Harris]

And here is a link to the plan:

GYRACE

 

I have one myself and have plans to convert it to a single rotor.

 

Here is a video I converted off a tape for a friend in the US Joel Waldo back in 2009, he converted his to a single rotored head. How's this for a bit of inspiration?

 Throw that stub wing away!

 

 

 

 

Rich

Edited By Richard Harris on 08/02/2013 22:53:55

Edited By Richard Harris on 08/02/2013 22:54:35

[Tom Wright 2]

Knew there was something suspicious about those rotors , just not to plan!

Tom.

[Stephen Jones]

Hi Tom ,

I meant Al`s Autogyro

[Stephen Jones]

Hi Richard ,

Do you have any info on how you converted the Gyrace to a single Rotor

Looks interesting i have two os 48 surpass`s one could go in it and the other in a Panther .

[Tangental]

This forum is a beast! I'm just getting back into RC again, refurbing my old stuff, dreaming of building vintage DeHavillands and now you want me to build egg beaters! Well, OK! So now I've got a lot of homework to do, so don't disturb me! I hope you're happy?

Tangey

PS

[Pete B]

Posted by Stephen Jones on 08/02/2013 21:41:31:

And you can see why it would not fly , but is it worth fixing or do i build a new one and i would prefer a auto gyro without wings , i suppose this could have a mast fitted .

I might be talking out of my hat but would the positive incidence on the blades have anything to do with it? I thought they were meant to have negative pitch.

Looks very repairable as is, to me - remake the dihedral brace, fix the covering and you're away.........

Pete

[Stephen Jones]

Hi Pete ,

I thought it to be very repairable too , Things i notice wrong with it are the wood support for the rotors has the grain in the wrong direction and so would snap off which has happened , crash damage maybe but i fear it would of happened at some point anyway .

Also although i know nothing of the set-up , the blades are heli blades and do not flex also they are attached to the head in a very ridged manor , my understanding is that as a blade sweeps forward it needs to rise and as it goes to the rear it needs to lower .

Of coarse i could be completely wrong .

What does anyone else think

 

Oh yes the thing i forgot to mention is that he could not get it to take off , he had to force it up .

And a foot of the ground it rolled in .

 

Edited By Stephen Jones on 09/02/2013 11:35:30

[Pete B]

I don't intend to expose my level of ignorance to the world at large, Stephen, but AFAIK autogyro blades are fixed and don't work in the same way as heli blades. There's a thread about the Gyrace over on RCG which you may find useful. The pics there seem to show the blades as having negative pitch.

I'm sure Rich or Tom will be along shortly.......

Pete

[The Whistler]

A couple of guys from my last club built and flew Cyril Carrs Kestrel, see here: **LINK**

Fixed pitch, flat balsa blades and counter rotating if I remember right.

Flew great.

Not had a proper look at the Panther free plan yet but looks good.

[Tom Wright 2]

Pete .

The photos Stephen posted do make it look if the blades are set at a positive incidence which of course, if they are, it would result in the blades trying to spin up backwards ..

The rigid attachment would ,as suggested,inhibit the flapping action that should allow the blades to flex up and down at different points around the rotational path.

I f the blades are flat bottomed it looks as if they could be used again after some minor mods .But they look heavier than DB had intended in the original design.

Perhaps the model is the result of changes carried out by the constructor ,and without the basic understanding of what is needed.

Tom.

[Stephen Jones]

Hi ,

Here is a close up of the rotor head and blades .

They are set to rotate in opposite direction to one another , they may have got bent on crash landing at the hub , as one pair seems to be set at positive and this pair at neutral .

Interesting to see both the gyrace and kestrel to have four blades .

And the blades do seem to have a flat bottom .Although i have put it back in the loft for now .

I would have thought that the flat balsa ones would flex where as these would not .

[Erfolg]

Stephen

When I look at the picture, I got the impression that the blades are under-cambered and upside down, as used on an aircraft. Is that right?

[Tony Smith 7]

Posted by Captain Slog on 08/02/2013 16:23:18:

Tony - Cyclic control is a term from helicopters, where the blade pitch varies or 'cycles' as it rotates to give to assymetric lift on the rotor disc to generate pitch and roll.

Autogyros have simple fixed pitch rotors that are not capable of 'cycling', so the term does not apply. The rotor disk acts like a wing and the whole disk is tilted in the required direction to generate pitch and roll.

David

Cheers. I was aware the cyclic controlled rotors were introduced early on (pre war?) but surfing around it looks like they were superceded by the two blade teetering setup, and the latter is used by aircraft like "Little Nellie".

[Richard Harris]

Stephen,

Boddingtons' Gyrace plan shows two different blade types, 3 and 4 blades. Neither type need to be on a flexible hub as they are counter rotating, the 4 blade is 1/8 balsa blades as with the DB Gyro. The 3 blade version has aerofoiled blades on an aluminium blade holder which has negative incidence 'bent' into the hub for each blade. This would need to be pretty accurate as one side woould spin up quicker than the other and faster. It would almost certainly cause a roll to one side if this was the case.

Rich