Folding vs. Non - Folding Masts

j bird

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Yeah, that's what SC just told me by email as a rough estimate. Did they mention if that included the joints for the push pull control tubes? If so, that might make the price seem a little more reasonable. I do know that it's a nice setup, with some damping for stick shake.
On a Dominator, all you would do with the push tubes is disconnect the Heim joints else top or bottom, simple!
 

13brv3

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On a Dominator, all you would do with the push tubes is disconnect the Heim joints else top or bottom, simple!

I built a Dominator years ago. No interest in folding control tubes. I only meant that the fancy push/pull tube joints would possibly help justify their $600+ price.
 

j bird

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I built a Dominator years ago. No interest in folding control tubes. I only meant that the fancy push/pull tube joints would possibly help justify their $600+ price.
I never said anything about folding push-pull tubes, if you disconnect the top 2 Heim joints they would just lay aside, doesn't your push-pull tubes have Heim joints on the ends? IMHO an engineered folding mast kit for $600.00 is reasonable..
 
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13brv3

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I couldn't find it searching here, but a general internet search found this thread, which mentions ordering the SC kit for a Dom. There are a couple pics of the mechanism installed on a SC as well.

 

Brian Jackson

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Here are a few Sport Copter image files I pulled off another builder's log site a couple of years ago for reference. I will try to find the log site because he described the process of prepping the holes through the redundant mast for the tube inserts. Some of these pics are various other builders' images which you can tell by the location of the plates. For example, image 1-4 has the plates attached to the rotorhead cheek plates while image 5-9 shows them attached at a split point much lower down on the mast tubes.
 

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All_In

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Bend (twist) but don't break to cut off your head???
What about creating a twisting shock absorber designed with an outside case of softer metal that would deform, after the shock past its limits, providing more torque absorption before it transfers to the attaching mast plates which would provide the last opportunity to bend not break?

Sound perfect to have a PRA Senior S.D.S.U engineering CAPA team project investigate it for us. But will have to wait until next semester.
 
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fara

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Here are a few Sport Copter image files I pulled off another builder's log site a couple of years ago for reference. I will try to find the log site because he described the process of prepping the holes through the redundant mast for the tube inserts. Some of these pics are various other builders' images which you can tell by the location of the plates. For example, image 1-4 has the plates attached to the rotorhead cheek plates while image 5-9 shows them attached at a split point much lower down on the mast tubes.

That's a decent design. I would suggest only one change (not crucial but recommended) and that would be to use folding mast plates of mild steel or medium carbon steel instead of 6061-T6 which is what these seem to be. Those would be better for crashworthiness in the gyroplane application. In trikes almost every mast is a folding mast so we have seen a ton of crashes and how 6061 as well as steel plates behave. Its not so important in trikes because the wing tip always touches the ground first and they aren't rotating so the energy dissipation is milder and different without much of a torque axis component that's significant. Also trike frames have a front nose strut triangulating the mast frame and a quarter inch thick 6061 plate is more than sufficient for a 6G load at 1000 pounds hanging load. However, most trike manufacturers still prefer to make a 3 sided mild steel plate box that's 0.125" thick instead because its does have better deformation characteristics in a crash. In the Revo trike we designed a 1/2" thick wall billet 6061 Aluminum 3 sided box (made from a solid 6 inch wide chunck machined down to 0.5" walls on 3 sides) for folding mast that was very strong but then the mast itself was a 2.25" 0.070" wall thickness 4130 curved tubing (as opposed to 6061-T6 tubing like most trikes) that did the job of bending and twisting instead of relying on deforming characteristics of the folding joint box.
 

fara

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Bend (twist) but don't break to cut off your head???
What about creating a twisting shock absorber designed with an outside case of softer metal that would deform, after the shock past its limits, providing more torque absorption before it transfers to the attaching mast plates which would provide the last opportunity to bend not break?

Sound perfect to have a PRA Senior S.D.S.U engineering CAPA team project investigate it for us. But will have to wait until next semester.

LOL ... K.I.S.S
Keep it simple. Someone who is experienced designing such structures can do what you are wanting above in about one day. Do not complicate something that has been done, tested and proven already. Twisting shock absorber? Next we will ask for an airbag :).
 

fara

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LOL ... K.I.S.S
Keep it simple. Someone who is experienced designing such structures can do what you are wanting above in about one day. Do not complicate something that has been done, tested and proven already. Twisting shock absorber? Next we will ask for an airbag :).


Wait I did the airbag in trikes already

 

j bird

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Wait I did the airbag in trikes already

LOL ... K.I.S.S
Keep it simple. Someone who is experienced designing such structures can do what you are wanting above in about one day. Do not complicate something that has been done, tested and proven already. Twisting shock absorber? Next we will ask for an airbag :).
Yeah, John gets carried away sometimes!!!!!!!!!!!!
 

13brv3

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Here are a few Sport Copter image files I pulled off another builder's log site a couple of years ago for reference. I will try to find the log site because he described the process of prepping the holes through the redundant mast for the tube inserts. Some of these pics are various other builders' images which you can tell by the location of the plates. For example, image 1-4 has the plates attached to the rotorhead cheek plates while image 5-9 shows them attached at a split point much lower down on the mast tubes.

Thanks for the excellent pictures Brian. I hadn't realized SC used the redundant mast.
Rusty
 

All_In

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LOL ... K.I.S.S
Keep it simple. Someone who is experienced designing such structures can do what you are wanting above in about one day. Do not complicate something that has been done, tested and proven already. Twisting shock absorber? Next we will ask for an airbag :).
That's is why I asked and did not just turn it in as a project.
Thank you.
 

All_In

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Yeah, John gets carried away sometimes!!!!!!!!!!!!
I represent that remark. But it is not sometimes...

I'm ALL IN, only have one way and it all the time looking for solutions and then try and make it happen 100% of the time.
HahahahahahahHehehehehehe
 
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