A part 103 tractor Autogyro?

[Aerofoam]

That reminded me of this photo that was posted around 20 years back- no idea about the origin. Thick Styrofoam with a glass lay-up. No idea if this ever left the ground.

View attachment 1161885

Wow! Very short!!! Very small engine!!

 

[wolfy]

Yes, I agree, but it's a lot of fun to fully exposed....So..., I would probably make a removable fairing for the front lower section and a windshield.
At 45 to 60mph, the drag factor is not a huge concern. For me, the ability to use it out in the desert on dirt roads is a major consideration, so this configuration holds up better than a pusher....
Here is a quick sketch of what I am thinking about. It is not to proportion, the front landing gear would be wider to accommodate rough landings
and be more tip resistant. The aft spar to the keel might have a shock strut to absorb the 2 rev. pulses.
The keel tube and wishbone would most likely be carbon fiber/S glass, or kevlar mix.

As far a bucket list, I will probably build it as a 2 seater, but this discussion was about an ultralight, which I think would be possible.
It would also save significant weight to use a Bensen style control bar......


View attachment 1161887

I like that

 

[Jean Claude]

At 45 to 60mph, the drag factor is not a huge concern.

According to my calculations, even at 45 mph, the engine requirement would drop from 53 Hp with no fairing to 41 Hp with faired airframe, despite the head keep outside and without tires fairing (on a base of 600 ft/mn clim rate)



As above airframe and 21" diameter rotor: 900 ft/mn expected with Rotax 503 twin-carb and 10 litres/h at 55 mph in level flight (270 lbs)

 

[wolfy]

Must be close to flying now is it JC?

 

[BrianInVa]

According to my calculations, even at 45 mph, the engine requirement would drop from 53 Hp with no fairing to 41 Hp with faired airframe, despite the head keep outside and without tires fairing (on a base of 600 ft/mn clim rate)

View attachment 1161893

As above airframe and 21" diameter rotor: 900 ft/mn expected with Rotax 503 twin-carb and 10 litres/h at 55 mph in level flight (270 lbs)

I’m a big guy, 6’2” and 275 pounds. If I did cover the frame, could I get away with the Rotax 503 I already have? I’m being told the 503 would be marginal and I need a 582 for the extra hp due to my weight.

 

[Jean Claude]

Yes, Brian, I think so too.
My weight is 175 lbs and my tank contains 9 gal US

 

[Doug Riley]

Reminder -- J.C. has already mentioned this, but it bears repeating: The slipstream from a gyro's propeller has a speed of 80-100 mph. This slipstream, impacting the pilot and the rest of the aircraft, creates drag in the same way as if the gyro were travelling at 80-100 mph. Therefore, fairing the pilot and tailcone is key to reasonable efficiency.

Various imaginative gyro builders over the decades have built un-faired tractor gyros. I'm thinking of the Jeri-copter, Ikenga, TRAG and others that long-timers will recall from the days of the printed PRA magazine. All were novelties that no one cared to duplicate AFAIK.

In addition to the high drag penalty, an unfaired tractor is unpleasant. That much wind in your face takes your breath away. Even more so if there's some engine exhaust mixed in (as is often the case). It takes some experience to become accustomed even to the 50 mph breeze in a pusher.

 

[BrianInVa]

Reminder -- J.C. has already mentioned this, but it bears repeating: The slipstream from a gyro's propeller has a speed of 80-100 mph. This slipstream, impacting the pilot and the rest of the aircraft, creates drag in the same way as if the gyro were travelling at 80-100 mph. Therefore, fairing the pilot and tailcone is key to reasonable efficiency.

Various imaginative gyro builders over the decades have built un-faired tractor gyros. I'm thinking of the Jeri-copter, Ikenga, TRAG and others that long-timers will recall from the days of the printed PRA magazine. All were novelties that no one cared to duplicate AFAIK.

In addition to the high drag penalty, an unfaired tractor is unpleasant. That much wind in your face takes your breath away. Even more so if there's some engine exhaust mixed in (as is often the case). It takes some experience to become accustomed even to the 50 mph breeze in a pusher.

All great points, thanks Doug. I’m a motorcyclist and snowmobiler from way back so I’d like to think I can handle the wind, and I plan on using my modular full face bike helmet, but to be frank I prefer a bike with a touring windshield now. I have no problem with devising a partial cockpit and tailcone fairing.

 

[Jean Claude]

Must be close to flying now is it JC?

I'm desperate.
After installing the brakes, replacing the carburetor floats that were sinking in, removing the nylon from the throttle sheaths that was melting on the cables, avoiding the fuel line vaporlock, checking the various engine temperatures, I'm now without an airfield to welcome me.
The sympathetic former owner has sold it to sectarian co-owners who won't accept anyone else.
I need a private aerodrome where I can learn to fly carefully with the direct control to the ceiling.

Thread 'my little wooden gyrocopter'

Aug 5, 2019

Many details to finish before the tests

• Jean Claude
• Replies: 66
• Forum: Builders Corner

• 
• 

 

[Aerofoam]

I'm desperate.
After installing the brakes, replacing the carburetor floats that were sinking in, removing the nylon from the throttle sheaths that was melting on the cables, avoiding the fuel line vaporlock, checking the various engine temperatures, I'm now without an airfield to welcome me.
The sympathetic former owner has sold it to sectarian co-owners who won't accept anyone else.
I need a private aerodrome where I can learn to fly carefully with the direct control to the ceiling.

Thread 'my little wooden gyrocopter'

Aug 5, 2019

Many details to finish before the tests

• Jean Claude
• Replies: 66
• Forum: Builders Corner

• 
• 

I'm having the same Bing issues on a 503 (they were flooding), I have had those carb issues on a BMW motorcycle with Bings and do not like them...
I have recently swapped a pair of new Mikunis on to the 503 as well as a new fuel pump and need to start testing.
I will post the process when I get it worked out. A pair of new Mikunis cost less than the rebuild kit for a single Bing and has far more parts availability for custom tuning.....

 

[wolfy]

I'm desperate.
After installing the brakes, replacing the carburetor floats that were sinking in, removing the nylon from the throttle sheaths that was melting on the cables, avoiding the fuel line vaporlock, checking the various engine temperatures, I'm now without an airfield to welcome me.
The sympathetic former owner has sold it to sectarian co-owners who won't accept anyone else.
I need a private aerodrome where I can learn to fly carefully with the direct control to the ceiling.

Thread 'my little wooden gyrocopter'

Aug 5, 2019

Many details to finish before the tests

• Jean Claude
• Replies: 66
• Forum: Builders Corner

• 
• 

I feel for you JC

 

[wolfy]

All great points, thanks Doug. I’m a motorcyclist and snowmobiler from way back so I’d like to think I can handle the wind, and I plan on using my modular full face bike helmet, but to be frank I prefer a bike with a touring windshield now. I have no problem with devising a partial cockpit and tailcone fairing.

You may be surprised by the difference.
An open frame gyro, you cop all the airspeed on all of your body, on a motorcycle all the front wheel, forks, headlight, headstock and possible windscreen reduce an amazing amount of the airstream.

 

[Doug Riley]

Decades ago, PRA Chapter 5 tested the parasite drag of a Bensen with a Dix body (a large fiberglass "tub" pod extending aft as far as the seat back), and compared it to the parasite drag of a naked Bensen. IIR, the drag difference at 50 mph was about 30 pounds. The Dix body obviously won.

Much better drag reduction can be accomplished by tapering the pod back over the engine, through the prop and ending in a large spinner. Very few gyro builders bother with this level of complexity, despite its advantages.

Of course, this same gradual aft taper is precisely what we see in tractor gyros (if the tail-cone framework is streamlined, not left open).

 

[BrianInVa]

I have the Brock KB2 now I picked up on Friday, and I’m trading the recently rebuilt Rotax 503 the seller included with it for a Rotax 582 on Monday.

I drew up a simple kindergarten level sketch of how the Brock mast, frame, fuel tank seat and controls and Rotax 582 would be grafted into the A-plane frame:

I’m going to look at an Affordaplane bare frame this Thursday:


So if there are any tractor configuration gyro experts here, please weigh in and either tell me what a friggin’ idiot I am now before I go any further, or offer some constructive criticism on how to proceed and what to avoid.

 

[Aerofoam]

I think there is a lot of extra weight in keeping any of the affordaplane frame and it would be easier to just start from scratch with the concept.
The mast may be a problem if it is so rigidly supported. The 2 blade rotor causes a 2rev. pulse as each blade comes around into the advancing position and some flex in the mast absorbs some of this, so the stick shake is not so violent.
Also, the landing gear should probably be significantly wider to give some stability to all the over head weight.
If you started from scratch, the frame could be a more graceful angled design with the upper tube angling down from the mast attachment to the tail and forward to the motor mount leaving a very large open area for the seat and controls. The mast to frame attachment could allow movement at the top to absorb the vibration. One gyro design had the mast in a big urethane tube bushing that allowed it to move 360.
A similar type soft mount could be built into the top of the frame....

 

[BrianInVa]

I think there is a lot of extra weight in keeping any of the affordaplane frame and it would be easier to just start from scratch with the concept.
The mast may be a problem if it is so rigidly supported. The 2 blade rotor causes a 2rev. pulse as each blade comes around into the advancing position and some flex in the mast absorbs some of this, so the stick shake is not so violent.
Also, the landing gear should probably be significantly wider to give some stability to all the over head weight.
If you started from scratch, the frame could be a more graceful angled design with the upper tube angling down from the mast attachment to the tail and forward to the motor mount leaving a very large open area for the seat and controls. The mast to frame attachment could allow movement at the top to absorb the vibration. One gyro design had the mast in a big urethane tube bushing that allowed it to move 360.
A similar type soft mount could be built into the top of the frame....

This first one will be a proof of concept for me. I’m not even that concerned about flying it myself. While I’m working on it, a friend and I are starting a Legal Eagle XL ultralight build. It will have a chrome moly frame and we’ll need to learn oxy acetylene welding for it. So after that I’ll be able to go back and redo this entire tractor gyro frame.

One thing I’ve been considering for the triangulation supports is mountain bike suspension seat posts to isolate/ dampen the supports from the mast vibration. They use elastomers which can be switched between soft and firm action, and make them for 430 pound riders - so shouldn’t three of them be able to isolate mast vibration?

 

[Aerofoam]

This first one will be a proof of concept for me. I’m not even that concerned about flying it myself. While I’m working on it, a friend and I are starting a Legal Eagle XL ultralight build. It will have a chrome moly frame and we’ll need to learn oxy acetylene welding for it. So after that I’ll be able to go back and redo this entire tractor gyro frame.

One thing I’ve been considering for the triangulation supports is mountain bike suspension seat posts to isolate/ dampen the supports from the mast vibration. They make them for 430 pound riders - so shouldn’t three of them be able to isolate mast vibration?
View attachment 1161914

There are a lot of shock type struts available from mountain bikes to motorcycles, I wouldn't use anything with small cast aluminum parts, they fracture.
The main shock for a rear mountain bike suspension might be ok if you can confirm the construction.
The main point with the mast, is it is probably better to leave the upper 3 feet unattached and preferably a round chro/mo section with some flex. There are also rotor head designs with s slider to damp the vibration.
I think you should leave the other plane alone and finish it as it is supposed to be, or sell it.
It's too much work to convert and if converted, it will be heavy....

 

[BrianInVa]

There are a lot of shock type struts available from mountain bikes to motorcycles, I wouldn't use anything with small cast aluminum parts, they fracture.
The main shock for a rear mountain bike suspension might be ok if you can confirm the construction.
The main point with the mast, is it is probably better to leave the upper 3 feet unattached and preferably a round chro/mo section with some flex. There are also rotor head designs with s slider to damp the vibration.
I think you should leave the other plane alone and finish it as it is supposed to be, or sell it.
It's too much work to convert and if converted, it will be heavy....

But in the end, it will be at least 50 pounds lighter than a Little Wing Autogyro by my calculations, even if it doesn’t make the part 103 cut off weight.

 

[BrianInVa]

There are a lot of shock type struts available from mountain bikes to motorcycles, I wouldn't use anything with small cast aluminum parts, they fracture.
The main shock for a rear mountain bike suspension might be ok if you can confirm the construction.
The main point with the mast, is it is probably better to leave the upper 3 feet unattached and preferably a round chro/mo section with some flex. There are also rotor head designs with s slider to damp the vibration.
I think you should leave the other plane alone and finish it as it is supposed to be, or sell it.
It's too much work to convert and if converted, it will be heavy....

Could the triangulation just be achieved with cables? Ron at LW Autogyros did mention it as a possibility.

 

[Aerofoam]

Could the triangulation just be achieved with cables? Ron at LW Autogyros did mention it as a possibility.

Not sure what triangulation you are referring to. I just think there is too much unnecessary frame design in that frame and you would be throwing good work at a bad design.
You could even just built the entire keel section from a single 4" diameter .125" wall AL tube and the rest of the structure could be smaller diameter materials. You would eliminate all the truss structure and weight.