RTK is getting a few flights in every week on his so he might be the best info source.

I would buy another, and probably will. I have run it both on an es composite pipe and on the stock muffler. My engine has not been babied and has about 7-8 gallons thru it now without any problems. The engine will run a little warmer than others, but if you baffle it (I didn't) it will run as cool as others. I have NOT had any sagging or over heating to date. No dead sticks either.
Since I had one of the initial engines made, Tom told me to run it hard to see what I thought, I did! Even ran it lean to see how it would respond, and it handled it well.
I have had 3 different engines on the same air frame, and the BME is by far the lightest and strongest out of hoover and has the best throttle response too.

Thanks RTK,

Now to find the appropriate airframe. Like I said before I have a BME 76 twin and its the most reliable engine I have seen. You can practically count the RPMs at idle and the top end winds up like an angry bull. Anyhow light engine big power gotta be a bipe. Maybe a model 12.

Robert

hey Robert , i'll be able to give you a small report as well by the end of this weekend. I'm doing a maiden flight on a little H9/ Carden yak this next weekend for sure , since the weather is going to be really good. I plan on doing at least 4-5 flights with it. It'll be all easy , break in type flights , but we'll see how that goes. I can't hardly contain myself sometimes.

PAT.....Dude i am so sorry man , i didn't see your post on the last page about storing a 35% bird here. I WILL have some room for that thing here really quick. I'm getting ready to frame some more block between my ceiling joyce's in my shop , and put some more hanger bolts in. Should have enough room to hang two extra birds in there within the next week or so. So if you are still up here in the area , just call me , PM whatever , i can make some room.

Well Jeff how did the weekend go?! I hope you had as many landings as takeoffs. Another question for you guys. Can this engine be mounted on DA standoffs or do you really need the width of the dowels?

Robert

The latest ones will have a thicker back plate (about 1/2 oz. more) for the crankcase and should withstand those standoffs without a problem, but it is still better to use larger standoffs that are tied together or other mounting. This will reduce vibrations by not allowing the engine to twist as much as with single standoffs. Believe it or not there is a difference.

I agree, way to much torque for any length aluminum stand offs. 7/8" hardwood dowels glued to the firewall should work just fine though.
BTW RTK and I did get to see a DA engine rip the firewall out of a SD Yak yesterday. It was on aluminum standoffs. The flexing broke the aluminum algle brackets on both sides. The engine died and the plane came down in one piece np.

Everything went really , really well! I had a lot of fun and got 4 un-eventful flights in. I had the 58 a little to rich on the bottom and just leaned a little 1/16th turns at a time and it started coming alive. I have the top set about right where i want it. It pulls this little 16lb 10oz yak around like it doesn't weigh anything.

I had one small issue , which i'm fixing right now. And it has nothing to do with the motor. The coupler between the header and MTW canister came loose on the first few flights and i didn't know it. So some real thick black gunk got all inside my cowl and motor box area. When i would hammer the throttle it actually "Pulls" the canister closer to the motor , and at idle , it would have about a 1/16th gap that was spewing crap every where. I took the entire front end off today and cleaned up the header and "knurled" it to help make the coupler stick better. And i'm also going to double clamp it it as well.

The BME 58 even after 4 real easy flights was acting better and better. It was ripping a VESS 23A at 7460 on the 4th tank....unreal! I'll run that prop for another gallon or so , then swap it back up to the Vess 23B for a while. Also...i had NO ISSUES with knife edge or inverted flight what so ever. The motor ran the same in any position it was sitting in.

I can say one other thing....i was nervous as heck! I flew the larger glow planes up until two years ago , but have been on little electric foamies for the past two years. Jumping up to a larger 30% was quite a leap! About like switching from a Cessna to a Boeing 747 i think.

If next weekend is nice , i'll fly both days and get some serious time on the motor.

Thanks guys. I have had the pleasure of being handed a transmitter where a 50 ripped the firewall loose on an GP Extra 300. The guy couldn't get the engine to idle down so he hollered for someone to help. As soon as he handed me the transmitter the engine ripped sideways and stopped. His kill switch was mechanical and the movement of the firewall caused it to disengage. Anyway I managed to pop it into an inverted spin and get it down. Very little wing and tail damage but the nose was all torn up.

As for the BME mounting. When you mount the dowels do you run lag bolts through the firewall into them or is there another method that is better suited like running the bolts all the way through and putting a nut on them? As for the mounting plate on top of the dowels could that be done with 3/16" CF plate or does it really need to be thick ply like some of the pics I've seen?

Robert

Use a bolt that runs all the way through, with self locking nuts (locktited) and fender washers behind the fire wall.

I go to the hardware store and get heavy duty blind nuts. The type that has 6 tangs is the stoutest but there's some good ones with 4 tangs.
After you get your holes and nuts and dowels all lined up tighter them down on the firewall to set the blind nuts. Get them good and tight. Then release them and mount everything back up with the motor. Just before tightening the bolts drip some CA on the dowels and quickly tighten every thing. Make sure they are close to the same length first or you will warp the motor mounting lugs.
One other thing, remove the engine again and sand the ends of the dowels flat after tightening and setting the glue. I use a hand size hard board and sandpaper. You want all four to touch evanly.
I don't know what you need the CF plate for. If anything else, some angle stock, one at each corner of the dowels to keep them from moving would be good but I don't do that with my dowel mounts, just the dowels.
Check for tightnes after a few flights and then again every 10 or so till you are sure they are done seating.

I was actually looking at the pics posted here.
[link=http://www.rcuniverse.com/forum/fb.asp?m=8584904]BME 58 Engine Mount[/link]

A 3x3 square of what looks like 1/2" ply that sandwiches the dowels looks like I would be adding back in all of my weight savings. Are you saying that the additional ply is not required?

Robert

I see what you mean. Thats just Jeffro. He was afraid his plane would be too light.
If my dowels were longer than about 2.25" I might cap them with some 1/8" aircraft grade ply but really the engine back plate and the firewall do exactly the same thing. True torsional stiffening would be shear webs between the dowels or angle braces to distribute torsional loads.
I just use the dowels. My 115 powered plane is on 2"x7/8" dowels, no bracing, 2.5 years of steady flying. I evan cut a large hole in the center of the firewall between the dowels to drop some weight and no problems. One other thing I do is to use a hole saw to make aluminum washers to cap the dowels. Metal washers work but aluminum washers cut from the same sheet have identical thicknesses.

Just putting the ply on the engine side and gluing would work fine. You could also stack aircraft ply and cut out the center and surrounding to match the mounting area as DA recommends and someone sells, or do what Altavillan mentioned.

yep Robert....those are my pics. I actually swear by the oversized wood dowl mounts. Most people have good luck with the small little aluminum stand off's....but i haven't! I drilled my BME 58's mounting back plate out to accept 1/4"-20's and then ran them all the way through the firewall. I then used some 1" or so fender washers with some lock nuts. Also Robert....the wood i used is like an imported cherry wood from Japan. I found it at ACE Hardware and it's extremely strong! Waaaayyy more dense than even oak! I could not even scratch it with a finger nail. Oak is actually really pourus , and has a lot of "hollowed veins" which can crack after a while. Also....i cut the dowl 1/2' shorter than what i needed , since i have 1/4" high grade ply on the front and rear.

Just word to the wisw....anyone using the nylon inserted lock nut....you are NOT supposed to use thread lock on them. I learned this the hard way on racing bikes for 30 years. the locktite softens the nylonn and after a while , the bolt will just vibrate off. I think it actually make the nylon "brittle". As some of my bolts , the nylon was just flaking apart when i used locktite.

here is another picture for refference.

Thanks for all the help on the mounts. As far as the aluminum standoffs most people that seem to have problems do not realize that they really shouldn't tighten them up against the typical firewall without something to spread the load and stop them from being compressed into the firewall. This creates a condition where they loosen against the firewall or weaken the hard point through it. The end result is always that the engine vibrates and torques putting a lot of stress on the tabs, the firewall, and the airframe.

I typically use a sandwich of at least 1/8" birch ply disks on both sides of the firewall and fender washers. This makes it so the ply doesn't compress and the torsoin loads are not reliant on the 1/2" diameter of the standoff. I don't rely on fender washers alone since they tend to concentrate the load on the center of the washer.

This thing looks like it would be a pretty good match for the Aeroworks Ultimate or Python. What do you think?

Got a 58 and trying to get it tuned. The low end and the transition are awsome however, with a Xoar 23x8 can't seem to get more than 6,330 out of it.

No matter what Ido I cannot get it to run rich on the high end. With the high end turned out 3 turns and the low end out 1 1/2 I still get 6,330 out of it. I can get the rpms to drop if Igo below 1 3/4 turns on the high needle as it starts going lean. Running 32:1 lawnboy and havea little more than 1/2 gallonthrough it. Does anybody have any ideas?

Robert

yep, i am running in to the same thing on my 58,can't get the RPM's to drop on the high end when going rich.i am out 2 turns on the high and 1-1/2 on low. i have read that after 2 turns out the needle is wide open?i have a Vess23-a and getting 7550[X(]!</p>

i am going to try a different carb, i have a HDA 48 off a 58gx2, i have always been able to get a good tune using that carb.</p>

Are both of you guys running a tunned exhaust??? and if so which type.</p>

On the stock exhaust you should be able to make it rich on the high end.</p>

Running the stockwrap around pitts. How many Rs should I be getting from a 23x8 Xoar? I would have assumed somewhere closer to the 7k range. This makes me concerned that the motor is running lean.

6900 is as fast as RTK's bm'er can spin a Xoar 23x8. But he is on a pipe. So 6300 might be a close number. What is a stock wrap around? If it's a Bisson they tend to be quiet but restrictive.

Altivillan, it would turnabout the same on the stock BME muffler, had the tune length on that dayway off. I should be able to hit about about 7200 now with my current set up (piped), that is if a xoar is a little more load than an nx23x8 or menz-s 23x8, if lighter loading I should hit 7400. Guy, which loads more a xoar or nx?? I keep forgetting.</p>

Closetguy,,,With the current carb you should be able to make it 4 cycle with the high needle, if not there is probably something wrong with the carb. You are really cranking if you get 7500 on a vess23a and a stock muffler, do you have a reliable tach??</p>

That muffler might be too restrictive for the 58, letit breath.These motors are happiest spinning around 7, and mine really likes 7600+ with a vess23a</p>

NX 23x8 seams to spin faster but it's been so long since I broke my last one... and I can't say if I ever tached it. I prefere NX but buying them here in Ca. sucks cause you have to pay shipping and handeling + taxes. Near doubles the cost.</p>

Some photos ofmy Aeroworks Pitts Python with BME 58 mounted.

I emailed Tom at BME to see if he has any ideas to help me get this motor tuned right. 6300 rpm's with a Xoar 23x8 can't be right and no way to fatten it up.

jmkibbon,- Is that with the stock BME muffler?? They are pretty open compared to other manufacturers, this might be one of your problems, but you still should be able to make it run rich.