engine mount

[tozz22]

i just bought this gyro and i am new to gyros.Is the way this motor mounted look OK.it seems to be mounted about 2in. higher than some motor mounts that came with the gyro.i was also wondering if the tail HS looks OK.any help or advise would be much appreciated

 

[jany77]

bee mount

bee mount

it looks like the bee from bakersfield /fresno area ?

also looks like cuyuna engine if thats is the case the prop should be 60" with about 2" clearance between the blade end and the boom than it doesnot mater if the engine mount is higher or lower as far as the prop doesnot hit the boom ,also the prop center line should be with center of the shocks

 

[tozz22]

thanks for the reply!,it is from bakersfield area and it has a cuyuna engine.i was just thinking the higher mounted motor might change the CG or make it more of a HTL gyro.do you know if it had a rotax engine if the prop would be in the same location of where it is now.the prop dose clear the boom by 2in.thanks again,Im new to all this stuff

 

[Alan_Cheatham]

Do a double hang test on the gyro first to determine where the CG is located on your machine, then you can measure the thrust line offset. Search the forum, there are several threads about how to do a double hang test.

.

 

[tozz22]

thanks! I'll look that up.

 

[Alan_Cheatham]

Some quick observations.............

As it is mounted there is no vibration isolation between engine and frame, but adding some will probably cause problems with maintaining belt tension as the reduction drive is not attached to the engine case. A redesign would be needed to fix the problem.

I'm not sure what the curved, looks to be black, engine mount is doing in the picture, it appears to not be bolted to anything on the gyro, but I can tell you that it was likely from a Quicksilver MX ultralight. The curved mounts were used on early MX's to mount Cuyunas and had a cracking problem where the mount bolts to the engine, I know because I have such a mount and it is cracked.

Highly tapered tail surfaces can run into stalling problems and is not a good design practice for low speed aircraft, even if it looks cool. May or may not be a problem on your gyro.

One thing that might become a fatigue issue is how the triangulation straps are bent and riveted on, make this a regular inspection point.

.

 

[Alan_Cheatham]

I was just thinking the higher mounted motor might change the CG or make it more of a HTL gyro.

All things being equal, raising the engine will raise the CG in relation to the thrust line, usually a desirable effect.
.

 

[tozz22]

thanks for your observations of my gyro,sounds like you really know about this stuff.i put that black motor mount in the picture to show how high my motor was mounted but i thought that mount went to a rotex motor or it was part of the bee plans.i didn't like washers between the engine and frame either.its probably safe to say,it would be best to put a rotax engine per bee plans and get a better tail.well i don't need those mounts and if you want them for your Quicksilver MX ultralight

 

[jany77]

mount

mount

if i remember the gyro has dragon wings but no prespin you should get at least the electric prespin from starbee gyros,its about 550$ and was made to fit the black beaty rotor head you have on your machine

 

[jany77]

mount

mount

as i was looking closer at the mount what i would do is make 1/4 plate mounted on the redrive and than use another 1/4 plate mounted on the angles and use quicksilver rubber mounts ,basicly the redrive bottom where the engine is mounted to the angle will basicly serve as botom of the mount easy and efective if you need some simple drawing let me know i can make some scetch for you

 

[tozz22]

that what i was going to do on friday when i get paid.my back yard is 800 feet long,do you know how many RPM starbee pre-rotar will spin 23 feet dragon wings

 

[Alan_Cheatham]

i put that black motor mount in the picture to show how high my motor was mounted but i thought that mount went to a rotex motor or it was part of the bee plans.i didn't like washers between the engine and frame either.

Ralph Taggart's original Gyrobee used a Eipper ultralight, bent engine mount but these went out of manufacture and so other Bees use straight mounts. There is, or was a page in the Gyrobee plans that talked about this mount.

On your machine the props thrust pushes directly into the airframe and does not pass through the engine case as in a more typical engine mounting. For this reason the engine mounting bolts are basically just holding the engine in place on top of the mount with little loads. The use of washers is to adjust for belt tension, I don't think you would have any problems with at least this part of the engine mounting, but I recommend finding a way to safety wire the bolts.

If the engine runs, run it and see what type of vibration you are getting into the airframe and then make a decision as to redesign to a soft mount.

Cuyunas have not been in manufacture for many, many years now, it's debatable if it will make a viable and reliable engine for a gyro.

Has the engine been updated with the flow-thru head?

.

 

[tozz22]

i think these are flow threw heads.

 

[tozz22]

the engine runs real good and dose not seem vibrate too much. i think i'll fly it the way it is,after i get some training first.

 

[Dirtydog]

tozz22 : You say you don't know much about this stuff, could I as how much training you have in a gyro also?


Look like a lot of items need to be addressed... on the tail you have aluminum sheeting that tool boxes are made of. not 60610-T6?. Is this the only place it is used? might have someone who knows look at it closer....:sorry:


Pictures above of the motor there is no fan blade on the motor??????????

 

[tozz22]

i do not have any training and I'm not going to try to fly till i get some training.as far as the tail i knew that it was going to need a new one,i bought it this way.the engine has a fan in it you just cant see it in the pictures.i have been interested in gyro for about 3yrs. now and read everything i could find about them,you gotta start somewhere

 

[gyromike]

The rudder looks to be too small also.

 

[tozz22]

thanks,i think im going to buy a starbee tail

 

[tozz22]

just wanted to tell everyone that i appreciate the input about my gyro,thanks

 

[Alan_Cheatham]

i think these are flow threw heads.

I can't tell from the pictures so I will describe what I'm talking about.

Cuyunas use inline or serial cooling of the cylinder heads, air blows first thru one head then moves thru the other. This is different than Rotax and Hirth which blow air parallel across both heads.

Because of the inline cooling Cuyunas had problems with the rear, or downstream cylinder overheating as it is being cooled by the hot air of the upstream cylinder. Cuyuna's fix for the problem was to reduce the number of cooling fins of the upstream head, so look at the number of cooling fins on each head, if the one next to the fan has less fins then you have the updated head.

Does your gyro have any history of being flown?

.