Robarts 550 reverse retracts
 

My only difficulty is sourcing a set of robarts 550.

The Robart site never refers to reverse retracts. Can they just have the trunion reversed? I was looking at the 550rs...

I really don't wish to use my stock retracts....

Underside mounting....
 

https://cimg8.ibsrv.net/gimg/www.rcu...eec299533a.jpg
https://cimg1.ibsrv.net/gimg/www.rcu...550550ab57.jpg

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https://cimg6.ibsrv.net/gimg/www.rcu...257c9a4c76.jpg
https://cimg2.ibsrv.net/gimg/www.rcu...14d39c73ee.jpg

I believe it dropped nearly 1cm... I doubt I can go lower. Opinions? Please note the egt probe is jutting out at 7o'clock

On most retracts the trunion fork can be reversed, mine had struts made from piano wire bend as needed and Spring air retracts.

All tailess airplanes need reflex up to fly level at 2/3 throttle, the farther aft the CG is located the less reflex up is needed, TO and Landings involves lots of Elevons to get off the ground and to return to the ground, CG location helps a lot on TO and Landings rotation, expo is your best friend, specially on the maiden flight.

https://cimg9.ibsrv.net/gimg/www.rcu...147f25d593.png
https://cimg8.ibsrv.net/gimg/www.rcu...6e975e1e28.jpg
The lower you get the engine the better, I think I see rubber grommets on the engine mounts, you don't need those, I recommend to use short screws and washers with nylon nuts ( the nylon nuts on top) this will give you room to rotate the engine to the Right as much as possible then try to lower the engine as much as possible, you may have to cut/modified the engine mounts a bit.

The grommets have a spacer in them to help the drop the engine even more, the clamp can't really be rotated coz of the egt probe attachment... Also, it goes through the glowplug.
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It a gas start mw44....
I never saw an actual yellow aircraft mount for the 44, so it's a bit of guess work.

Second picture option is the lowest I could go. I believe if I could get it to nearly touch the fuse would be the best to keep it close to the thrust line... Am bummed at the moment!

The P80 got the glow and probe close to each other.

I might try rotate the tail cone to make the probe read from top....
​​​​​​But the glow plug ring is like the anti rotation pin for the engine in the mount...

Not to worrie, we all get that way when an airplane give us so many challenges ( problems )

Post a picture of the glow plz.

Tks.

You bet!!! First problem was the brakes....
Now sourcing the retracts....
Getting that darn Wren as low as possible!!!!

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The airbrake looks good.

https://cimg8.ibsrv.net/gimg/www.rcu...3b2a5f986.jpeg

The egt prove is at the 7o'clock...
https://cimg2.ibsrv.net/gimg/www.rcu...a9570be0f3.jpg

Same mount as mine...glow at 2o'clock

I see what you mean with the glow plug, skip that and rotate the engine to the Right.

I believe Wren was the only one that added that ring to their mounts.

I need to rotate the tail cone too... To get the egt probe up too...

The egt mount is on the same bracket.

Make sense?

https://cimg7.ibsrv.net/gimg/www.rcu...9691c00cf2.jpg

The probe would still be a problem! Since the mount keeps the darn sensor always at 7oclock!. If I skip the glow, still the egt won't turn in relation to the mount...the mount is part of the egt bracket

Thanks. That am very satisfied with.

On the Kangaroo because the engine is mounted so high the engine has to be mounted with the rear up to help it rotate off the ground, you may have have to do the same to some degree, it may end up with some, not much or nothing.

Yes, do that, rotate the tail cone, it can be rotated any way you want.

Do not over tighten the screws when you put them back on, set them, then 1/4 turn more, after you run the engine you can reset them again.

Thing is I have no drawings of the thrust line vrs longitudinal axis. So have no idea of the aircraft had any upthrust.... I know it need reflex like the hotspots, but upthrust?

The mount would still mess me up. Since it's part of the bracket. The egt would not be supported in any way then...

Unless I flip it (the bracket) over and under!!and I get the sensor next to the probe.....

It's 2300 here... And and seriously considering to go get it done!

If you had enough of it, take A few days break, I do that then I'm back with fresher thoughts.

You could build a separated 90° support for the EGT then slide it under the engine mount like we do with the smoke sticks, going to take a picture of the smoke stick.

I will try to the flip the bracket over by 180degrees....
Will see how low I can go then...
Brackets are not an issue, I can re bend, re cut or fabricate. As long as I get what it takes. My concern is upthrust. I have no idea if any is needed. I might just add 2degrees... And see how it behaves.

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I don't recall if mine had any up thrust, I don't think it did, I have a friend that had one, I will ask him about the engine up thrust.

​​​​​thanks!!! That would be appreciated!

Good point of making a bracket to slide under the mount....

Giving up thrust will help any time, you get to find the effects during flight, when it is going faster it wants to climb a bit then you push the Elevons down a bit then back to normal cruise speed ( 2/3 throttle ) all is back to normal trim.

These tailess airplanes are a diferent animals and your Stingray will fly a bit different than mine or my friend's, but it will fly and it will scare the pants off you :) and you are going to want more of that for sure because, it will be so much fun to fly her.