My Engine

[treaze]

Ok, I'll try this again. The forum went down on 11/2, and swallowed this new thread of mine. Which is maybe just as well, because I flip-flopped and now have decided on the Rotax 447 instead of the MZ201 that I had originally intended.

In prep for that, I've been looking at what I need to do for the engine bearers--and I figure I must be missing some documentation. Or maybe none ever existed. All I've got are Ralph's plans that I've been working to, and Session 5 from his site where he seems to be picking up midstream what it takes to mount the engine. What I know so far that I'm missing:

1. Bearer thicknesses and widths? I assume they're 6061T6. Are they all 2"? And 1/2", or is 3/8" ok?
2. Hole locs and sizes?
3. Barry mount ident & hardware info.
4. I see people using downtubes, but I find no discussion or definition of them. Is that just a Starbee thing for a little extra support? I know they use a different horiz engine support arrangement--I've built mine to Ralph's phase 6. Can a UL do without them?

Another relevant thing: I've got a note to myself from long ago about oil injection. My impression was that there's an oil injection option on the Rotax 447, but that may entail moving the engine farther aft on the engine supports. Has anybody done that? It may not be worth the expense, weight, complexity, and cost, but I thought I'd ask upfront so I'd know. Not having to mix oil & gas would be great.

Thanks!

 

[Dirtydog]

treaze :

The engine mount I built were out of 6061-6T 2" wide X 1/2" thick.
Barry mounts I used the med. not the hard or soft. I ORDERED THE YELLOW AND WHITE ONES

BARRY ENGINE MOUNTS
RED and WHITE------------Soft
YELLOW and WHITE---------Med
GREEN and WHITE----------Hard

Hope this help!

https://www.rotaryforum.com/forum/attachment.php?attachmentid=52209&d=1232061266

 

[treaze]

My Engine

DD - Hey thanks! I appreciate the pics. I've spent all day trying to sort it all out. Geez, there's so much information out there--the task is to try to figure out what's relevant and make some semi-informed judgements. I still wish I knew if Ralph called out 1/2" thick bearers as necessary, or where that dim came from.

Anyway, it seems that 2201-2 in DD's 1st pic is a bogus or outdated number--because I can't find a reference to it anywhere--but I do notice it shows 3/8" plates rather than 1/2". There is a 22001-12 medium mount with the white/yellow id that DD mentions, and Aircraft Spruce sells it under not Barry but Lord engine mounts. A site called novibration recommends the use of "snubbing washers" 9810145-01804 with them that Aircraft Spruce also sells. Novibration also calls out 3/8" plate thicknesses, so I wouldn't know what the effect of using 1/2" bearers would have on the mount's effectiveness. Novibration's diagrams also show "support structure" and "isolated structure." Wouldn't "support structure" be the engine bearer and "isolated structure" be the airframe? I can't figure out which is which in engineer-speak. But if I interpret that correctly, then everybody would seem to have their Barry mounts installed upside down--but to any ill effect? Who knows.

The unidentified 3rd pic is possibly the obsolete and unobtainable Eipper engine mount assy that Ralph describes. It calls out LEAF H6142 mounts, so maybe that's why people may be continuing to use them nowadays. I notice the lower bearer is 2" and the upper is 1-1/2"--I wonder why we can't still do that? And I wonder why the thickness spec is omitted--not helpful. If you'll notice on the pic, the bolts are 5/16", so these are apparently different mounts than shown on the 1st pic, which use 3/8" bolts. What a tangled, confused mess. I think anybody who successfully builds one of these machines to completion is a real magician. What to do, what to do...

Very frustrating. I hope somebody can shed some definitive light on all this. What have people been using?

Oh, btw, this forum thread is very relevant, too: https://www.rotaryforum.com/forum/showthread.php?t=16834

 

[treaze]

My Engine

I think I've figured out a few things. If you start at Ralph's site (https://taggart.glg.msu.edu/gyro/gbee.htm) and go to "Don and Ralph Build a New Gyrobee," and then to "Mounting the Engine," you might start getting the impression, as I finally did, that this was not a how-to by Ralph of how to mount the engine, as I thought and hoped for in the absence of anything else, but is instead a description of how to process an engine mounting kit bought from Starbee. That's why so much is undefined--it's already provided ready-made by Starbee. But using some photo-analysis techniques, it seems apparent that all four bearers are 2" wide and 3/8" thick. And unless you want to use downtubes, as you might esp if you use Starbee's single horiz engine support tube, all bearer lengths can be 10". So now I can finally order my basic materials. Progress!

And luckily, I can barely make out 22001 on a couple of the pics of the mounts. So I feel confident in ordering Lord medium 22001-12 mounts from Aircraft Spruce. I have an email in to them and to Barry Controls re the use of snubbing washers and installation instructions. Re the orientation of the mounts, I finally found a pic somewhere of what I'm thinking might be correct--see pic. It's opposite of anything else I've seen so far--rubber is on each side of the upper engine bearer, not at the structure bearer. We shall see. Stay tuned!

 

[treaze]

More revelations. I finally found that DD's #3 unidentified pic of the bent mounts--the dwg that was missing the material and thickness specs--is the last page of Ralph's Phase 14. And the unidentified page just before that says it's 6061T6 and the thicknesses are 3/8". So that part of the mystery is solved.

So I now seem to be presented with a dilemma--should I go with that was initially used while it was available (2" wide lower bearers, 1-1/2" upper bearers, and LEAF H6142 mounts with 5/16" bolts) or should I go with what Starbee is apparently providing (2" wide upper and lower bearers with Barry/Lord 22001-12 mounts with 3/8" bolts.)?

Does anybody know of an unsatisfactory service history of the former config? It'd be nice to use that if it had been working out ok, because it'd be lighter on my Part 103 gyro. Was there some compelling reason to enlarge the upper bearers from 1-1/2" to 2" and to go to heftier mounts? Or was that just to be extra safe for those not concerned with weight?

 

[Dirtydog]

treaze :
I belive that everyone is using the Barry mounts.

 

[treaze]

My Tail

My Tail

After a lot of searching around, I finally ordered most of what I need for my engine bearers today--misc hardware from Aircraft Spruce, 4' of 2"x3/8" 6061T6 bar from onlinemetals.com, and 22001-12 med Barry Controls mounts from Wicks. From my researches, I found out that apparently nobody really seemed to know for sure how to assemble their mounts onboard, probably because, inexplicably and incredibly, Barry does not furnish installation instructions with their products (just a hard-to-find online version that doesn't seem to apply). I called Barry to find out (have you ever tried to communicate with an engineer who converses only in Engineer-speak vs ordinary English?), and got nowhere. Frustrating! So I resorted to emailing him pics, and by a process of elimination, he admitted the following was acceptable (with ref to the attached pic of a random typical installation I collected from this invaluable Forum):

From the top down:

Bolt head (AN6-tbdA),
washer (AN960-616),
3/8” engine bearer,
B-C 22001-12 “bushing",
3/8” aircraft structure,
B-C 22001-12 “ring”,
“rebound” washer (AN970-6),
washer (AN960-616),
nut (AN365-624A)

The "bushing" is the stepped conical shaped piece. The "ring" is the disc shaped piece--don't reverse this order.

In addition, he cautions to put 0.040" radii on hole edges, and that improper installation can have an adverse effect on performance and fatigue life. I abandoned any effort to determine if there were any alternate configs acceptable, or what any adverse effect of using 1/2" bearers might be (or not). If you want to contact this guy, he's JJ at (508) 417-7044 and his email is [email protected]. Good luck. Ha ha.

 

[treaze]

Onlinemetals.com delivered today--too bad it was the wrong metal, too short, and it was even bent! Sheesh! How bad can you get? At least they were prompt.
I've been locally accumulating misc stuff and tools for building the bearers, and I've got a few questions. (1) Ralph says what to get for the metric hardware for attaching the upper bearers to the engine. But shouldn't a flat washer be included in the list, so the lockwasher digs into that instead of the bearer? And, btw, if his "standard" is really "coarse," then the nomenclature for those bolts is M10-1.50-30 (found at Lowe's). I've been learning about such stuff! (2) Prompted by not being able to find any metric drill bits, I'm wondering if it might be a better idea to drill the 4 engine attach holes slightly oversize, anyway--to facilitate installation if the holes aren't precisely on target. Any comments on that? I wonder what size Starbee drills them? Anybody know? (3) I am having zero luck finding a 3/4" straight chucking reamer that will fit in a 1/2" chuck. Can anybody give me a source? I've checked at least a dozen places, and all the shafts I've found are at least 5/8". Thanks!

 

[Redbaron]

hey terry, I feel your frustration about receiving bent metal, sheesh!
I wish I had some 3/8" aluminum stock and I would just build you some!


do you have a drill press terry? not sure if you have said before!

 

[Alan_Cheatham]

Terry,

This would be my recommendation as to mount installation (revised drawing), Berry's attached to the airframe mount and the engine mount vibrating within them.

.

 

[treaze]

My Engine

Dirtydog - Yes, I have a drillpress--why do you ask? Which reminds me, I did finally find a place that could special-order a 3/4" reamer for me, for big bucks, and it'd take 2 weeks. But then I thought I should just see how good I can make those holes with just the bit, which is a nice new one, put a large chamfer on the edges, and then squish the rubber into 'em and forget it.
Alan - That graphic you and Dirtydog came up with is sure a good one--why couldn't Barry Controls do that good? And I personally have no problem with either configuration. But neither one jibes with what the tech reps at the Barry company tell me to do--so I'll stick with that. I hope somebody else does talk to them, though, to see if they'll admit to any other alternative configs that they'd bless. Btw, I did a bunch of crude old fashioned cut and pasting, and came up with the attached image to illustrate what they said is corrrect. Sorry for the quality. Maybe somebody can work up something better.

Btw, I realized something: There's only 1/2" vertical distance between the upper and lower bearers--even before the rubber "bushing" is compressed at all. The metric bolt head in between is 3/8" and the lock washer if squashed down flat would take up almost the remaining space, and would leave no room at all for a flat washer. So what happened here? What's the fix? Add fender washer(s) at the top of the "bushing"?

 

[Redbaron]

Heres a pic of how I did mine, terry! I forgot where I got the idea, I think it was from ralph taggarts site but I can't remember. My engine mount bars are 3/8". The lower engine bearers mount to the engine rails with 1/4"an bolts in a staggered fashion so they don't hit the 3/8" metric bolts that attach the upper engine bearers to the engine! :wacko:


one other thing is put some vaseline on the barry mounts before trying to insert them in the 3/4" holes!

 

[treaze]

Redbaron - Perfect pic! Thanks. I kinda wondered why the 1/4" bolts were staggered--I figured it was just to provide a bit extra stability. In any event, I was going to go with the flow with that, if I ever got to that point. And I see you've added multiple spacing washers at the top of the bushings to give some extra space between the bearers--just what was needed. I hadn't noticed that in any other all the other pics I've looked at.

 

[Redbaron]

I added extra washers at the rear engine bearers, this helps get the engine thrust line more in line with the flight path and slightly helps for a slight high thrust line! i think doug riley did the same thing! Just as a side note my bee's airspeed tends to bleed off at cruise when I let go of the stick indicating I have either a low thrust line or too much negative pitch on the tail! I'm fine with this knowing it won't kill me if the rotor unloads!

Redbaron - Perfect pic! Thanks. I kinda wondered why the 1/4" bolts were staggered--I figured it was just to provide a bit extra stability. In any event, I was going to go with the flow with that, if I ever got to that point. And I see you've added multiple spacing washers at the top of the bushings to give some extra space between the bearers--just what was needed. I hadn't noticed that in any other all the other pics I've looked at.

 

[treaze]

Redbaron - So you actually tilted your thrustline a little bit? I think that's a little too sophisticated for me at this point, so I'll just add an equal number of washers all the way around. I'm glad I didn't order the bolts yet--I'll see how long they actually need to be after I get it all put together. I know Ralph just estimated AN6-22A's, but he doesn't say what he ended up with or if he added extra washers to give him more of a gap between bearers. Btw, I ran across a site that gave instructions for installing a 447 in a FW homebuilt--and they used the junk shipping studs! Ha! Thanks for saving us, Ralph!

 

[PW_Plack]

...Just as a side note my bee's airspeed tends to bleed off at cruise when I let go of the stick indicating I have either a low thrust line or too much negative pitch on the tail...

Someone correct me if I'm wrong, but isn't this is just a trim spring tension adjustment issue?

 

[Passin' Thru]

Someone correct me if I'm wrong, but isn't this is just a trim spring tension adjustment issue?

Exactly correct! :sad:

 

[Dirtydog]

treaze :
I used grade 8 bolts until I got finished then switched. Sorry I have been on Vacation all week....

 

[treaze]

DirtyDog - Yeah, that's what I got, too--from Lowe's. They're id'ed 8.8 on the head. Ralph mentioned they're ok. Do you remember what size holes you drilled in the upper bearers for them? I was thinking of going slightly oversize, to help alignment--probably 13/32".

 

[Dirtydog]

Treaze :
Going back reading the post I belive you had me mixed up with ( Redbarron) !
I already knew you had a drill press.....
I can't remember what size bit I used right off the top of my head but I did tapper the hole at the top so it would not cut into the Barry mounts.

Dirtydog - Yes, I have a drill-press--why do you ask? Which reminds me, I did finally find a place that could special-order a 3/4" reamer for me, for big bucks, and it'd take 2 weeks. But then I thought I should just see how good I can make those holes with just the bit, which is a nice new one, put a large chamber on the edges, and then squish the rubber into 'em and forget it.