Anyone using a BME 50? thinking about putting one on a profile.
Any good, bad, or ugly, about this engine?

Buddy has one, its a sweet runner, still breaking in but pulls about 7000 on a 22x8 I think is on it

I have a BME 50 on a DP Extra 330L. Love it....Started correctly right out of the box, and pulls like it was made to fly.

Lucas:

I agree, super engine. Have one on my GP Patty Extra and would not hesitate to buy another in the future. But I do have a question for you (or something you may not have thought of), if your installing it on a profile, how do you intend on keeping the carb out of the air & prop blast? This may become a issue once the plane is in the air. With the carb hanging out into the open it's bound to go rich and start the burbling thing. This will happen with any gas engine's carb that's out side of a cowl (and then again it happens sometimes with a cowl). Just a thought...Unless there's a cure for it when used on a profile. I'd be interested in knowing about it as I've thought of a gasser on a profile and never did it because of this issue. Any thoughts?

Im putting together an Aeroworks profile with a new BME50 on it.
I was kinda sceptical about the weight on this plane but it needs the nose weight anyways.
I called up Aeroworks to ask if they had heard of any with BME 50s on them and the owner told me he has one and so do 4-5 guys at there field with this exact combo.
He,Roco,said it ROCKS. Tons of power and still balances out with no issues.
Im looking forward to flying it.

Good Luck

Dave

If you use a vent tube should not have any problems of which you speak.
I have a freind who has one ready, but has not flowen it yet, was at the masters at Joe Nall said it was way towindy for the little one. It should fly great just was wonder about the BME 50 sounds like a good little motor.

Lucas:

I thought of that (the vent tube trick), but the whole carb is hanging out there in the wind. I was just wondering if that's going to present a problem or not. Sure there's gassers on profiles, I'm just wondering if it's going to present a problem or not and if not how do the guys/gals get around it.

Also, don't wonder...The BME50 is a great engine. Out of the box it started on the 2nd flip (after a pop with the choke on). Every gallon through it, it got stronger and stronger. Never a starting issue, never a power issue, just follow BME's instructions and it's one fantastic little engine. I'd buy another.

3DFalcon:

That's got to be a freakin' rocket ship!

Edited because my spelling suc*s...

For rcpilotjae-RCU: I just bought a GP Wagsstaff 1/4 scale & I'm thinking about a BME50. Did you have any installation problems & since I'm new to gas engines, what else will I need besides a kill switch? Also, what maH battery should I use for the ignition? Thanks for your help!

JC

I had an Aeroworks profile with the BME 50. The BME 50 is and outstanding engine that has unlimted verticle with 16lb planes and is extremely reliable.

Two problems, its very hard to get sufficient space between the engine ignition components and the radio gear. If you haven't ordered your BME yet then make sure to order the Bosch cap with it.

Second, when the BME was idleing the profile fusalage looked like it was made of rubber. It really shook, it moved at least 3/4 inch rotationally as the engine idled.

I lost the plane on the 4th or 5th flight due to radio interferance. I know many people blame thier crashes on this but the plane flew over head and as it got 45 degrees off my right shoulder it went into a slow rolling dive. I had plenty of time to work the sticks. I pulled back on the throttle and held the transmitter high over my head but nothing made any differance as it slowly dove into the trees.

Joe

Schipmunk:

The switch you use to power the ignition with the battery pack is your kill switch. In other words, use a heavy duty switch (JR or MPI, the same type you use on your receiver pack). Hook this up between the battery you plan to use for your ignition and the ignition's power wires. This will turn your ignition on & off and (of course) act like a kill switch as it's cutting the power to the ignition. No power (battery pack) no spark for the engine. I've been using a 1400 mHa 4-cell pack NiCad for my BME50 ignition. You can get a bit over 2 hours of continuous use with that amount. Some guys use more, some use less.

As far as installation of the BME in the GP Patty Extra, there's no issues at all. In fact you can even use the motor mount they give you for a glow engine. It's big enough and strong enough for the BME50 and since the BME fits a standard motor mount it's a easy setup, just like a glow engine. Some guys swap out the GP motor mount with a metal one. It's a good idea, but not necessary. When you do this, let me know and I can post some pictures for you on how it's done and how the cowl gets cut out.

If your concerned with RFI from the ignition here's what you do. Most of the BME50's that are out there have the old ignition on it. Actually it's the same ignition module, but there's upgrades you can do (or CH can do) to make RFI almost non-exsistant. First is to change the rubber boot spark plug cable with a Bosch cap. (With the Bosch cap you will need to change spark plugs to a short 3/4 hex by 14mm plug. Not a big deal, they are available from your local car parts store or CH and brands are NGK or Champion.) It's just because the Bosch cap only fits these size plugs. The second thing you can do is to replace the hall sensor wires. CH has a upgrade that includes a grounding wire which makes all the difference in the world in keeping RFI from getting back to your receiver. If you have your BME, look at the wires coming off the hall sensor. There's 3 wires there. If you have 4 wires coming off the hall sensor (at the engine) then you have the new ground update. If you only have 3 coming off the sensor by the engine then you need to up grade it to the 4 wire system.

Now, I successfully flew my Patty with the old rubber boot and 3 wire systems all summer long. I had a couple glitches, but nothing serious. When I built I took the time to follow the rules and keep all your ignition & ignition battery & switch at least 12 to 18 inches away from the receiver & it's battery pack & switches. Now that I upgraded the system there's no glitches or RFI at all. Quite a improvement and I feel much safer now.

I'd be glad to answer any questions you have about the Patty. Just ask. I'm on my second one, because I like how well it flies. It's outstanding.

RcPilotJAE: Thanks for all the great info. I've been flying for about 20 years, but this will be my first gas plane & it's kinda like starting over to learn about a new system. I actually had a Moki 2.10 to use, but I sent it back & should get the BME50 this week. I was at a fun fly this weekend & saw a CAP232 with a BME50 & it was awesome---plenty of power! I also have 2 Ceramark HD switches coming.

For the tailwheel, do you have problems with it "catching" on a grass field? I bought a Sullivan S861 tailwheel & I'll be using it----it was recommended in the RC Modeler review.

It would be great if you could post some pictures of your cowl & how to cut it out.

Have a great day---JC

RcPilotJAE: I forgot to ask you, what kind of battery pack are you using? I'll have 5 HiTech digitals & one standard servo (I'm going to set up the pull-pull on the rudder) & I have a 2000 mAh NiMH battery for the receiver. Do you think this will be enough or should I have more?

Thanks--JC

Schipmunk:

You are very right, when changing to a gas engine it's like learning all over again. In fact when I did my first 33% plane, it was a real learning experience. Everything I knew about building and wiring .40, .60 & 1.20's was thrown right out the window. The big birds don't use your regular control horns & clevises and rods. They use ball bearings, rocket city horns and titanium turn buckle rods. Servos get ganged together and need to be adjusted so as not to fight each other, etc, etc. Bigger batteries and regulators need to be used, etc, etc...Yes, it's a whole new world.

But, I found with the GP Patty Extra, changing any of the parts they give you in the ARF is a personal preference thing and type of flying your going to do with it. Everything they give you will work fine and be strong enough, except the tail wheel. After about 20+ flights it was a mess and I changed to a Ohio tailwheel setup. Don't get me wrong, the tail wheel they give you is OK, but not great. It will work on grass or pavement, but it just doesn't hold up and the wheel itself is a bit too small. Best to change it as your building so you don't have to do it later. And use at least a 1&1/4 inch wheel. I have a 1&1/2 inch on mine. Works fine and the Ohio tailwheel setup is very sturdy. Also (personal preference again) is to throw away those foam wheels they give you for the mains. Get some good Du-Bro feather lites or any brand with real rubber on it's wheel hub. I've always hated those foam things. (But it's a personal preference thing, other guys/gals love them.)

The HiTec digitals are fine. You didn't say which ones they where. The 56xx series is fine for the Patty, the 59xx series is over kill (IMO). Heck, myself and a lot of guys that fly 35-40% planes use the 59xx in these big planes. That's why I say the 59xx are over kill. The 56xx are a sport digital made for planes in the 80" range. They are cheaper but you still get tons of power and a good digital servo. (For your FYI, the 56xx uses a cored motor, the 59xx uses a coreless motor). In fact I would be using the HiTec 56xx in my Patty if it wasn't for the fact that I had five JR8101's hanging around and they where new. These (the JR 8101's are a 90oz in torque servo with wide spaced ball bearings and a coreless motor) are plenty strong enough for the Patty and (of course) why buy more when what you have will do. This hobby does get expensive!

Now, on to the subject of Pull-Pull with the BME50 up front. Your going to have a balance problem. The BME50 w/muffler is about 3.6 pounds. A little heaver than a big glow engine, but not by much. I found with the servos for the rudder in the tail (along with the elevator servos) that all I needed for balance was to move my battery packs around. I use a I4C Isolator so I have one 2400 mHa 4-cell pack on the servos and one 1100 mHa pack running just the receiver. (My 1400mHa ignition pack is mounted right next to the engine on the motor mount.) So figure I have the engine, the ignition & the ignition battery pack all on the motor mount, servos in the rear and all I did was move the 2400 & the 1100 pack a little behind the receiver/servo tray in the Patty and it balanced perfectly, by the book. Now I know a lot of guys did use Pull-Pull with their Patty, you may want to ask them or maybe they'll jump in here and help you out. All I know is if you where to use a Pull-Pull with the setup you've got planned your going to end up having to put some serious lead in the plane to make it balance. Then again, maybe not. The guys that have done it would give you better advice here than I can. If you look in ARF/ARC right here on RCU there's two huge threads on the building & flying of the GP Patty Extra. Both threads are excellent, just read through them and you'll probably find out what will be needed with the Pull-Pull and balance with the BME50. You can't miss these threads, thousands of replies and excellent advice. Lot's of pictures too.

Back to your last question (I'm rambling here)...the 2400 should be plenty enough for the receiver and servos. Even though I use a 2400 for servos and a 1100 on the Rx, I could eliminate the Isolator and just use the 2400 and be fine. You'll have enough power for five 10 minute flights before you'll need to charge and still have juice left (but always check your battery with a good volt meter and a load between flights to be safe, but after 20 years, I'm sure you know that).

I have to take my cowl off my Patty tonight for some maintenance. I'll snap a couple of pix and put them here by tomorrow for you. You'll be able to see the Bosch cap and the 4 wire hall sensor on the BME, etc...

Schipmunk:

Quicker than I thought. Here's a couple of pix. Look close at the hall sensor, you'll see 3 wires go in and the 4th wire is connected to ground on a lug, under the bolt. This ground wire just gets wrapped around the rest back up to the ignition box. IMO, it just shields the 3 main wires, helping to suppress RFI. The stock one doesn't have this, you could easily add one.

Hopefully you'll see the Bosch cap, it's not tightened on (I had to take it off to get the cowl off, so I just stuck it on the plug for the pix).

The brown you see in the fins is spilled red locktight I used on the muffler bolts. It speeped through the holes and made a mess. You'll see the ignition on one side of the motor box and on the other side you'll see the 1400 mHa battery for the ignition. (You'll also notice the throttle linkage is undone.) The clevis is a metal sullivan, but the rod is a all plastic 'Golden Rod' by Sullivan to a standard HiTec 425BB. Makes a good throttle servo. This BME50 has had a new crank put in it and a new carb. (Don't ask, or maybe you should!)

RcPilotJAE: It sure does help to hear all this info. How do I hook up one battery for the receiver & one battery for the servos? Here I go with a stupid question, but I think it has something to do with the I4C isolator (I don't know what that is).

Hi rcpilotjae, Is that a great planes adjustable mount? By the way nice neat setup!
Floater.
[sm=thumbup.gif]

Schipmunk:

A Isolator is a device that separates the servos from the receiver. There are many different kinds and manufactures out there. In the Patty I use the I4C Isolator. In general they allow you to use a bigger & separate battery for the servos and then isolate the servos & their power from the receiver. You then use another battery for the receiver. It 'isolates' the servos from the receiver so you don't get any servo noise or RFI back into the receiver (because they are now separate circuits). Electrodynamics makes one (I think it's called the glitch buster) and instead of being a mechanical isolator (like the I4C) it optically isolates the servos from the receiver (which IMO is better). Optical is always better than mechanical because with mechanical there's still a chance of noise getting to the isolated circuit. With optical it's impossible to get noise to the isolated circuit because light waves can't pass electricity, only 0's & 1's (zero's and ones). It also allows you to use a bigger battery on the servos, say a 6V 5-cell pack at 2400mHa and a regular 4.8v 4-cell 600mHa pack for the receiver. Since there's no power being taken away from the receiver (by the servos) the receiver can run on a smaller pack and last all day long. (Just charge your servo pack when out at the field.) Here's a pix off the I4C site that shows what I mean. (Disclosure-Picture borrowed from the I4C web site.)

Floater:

Yes, it's the same adjustable mount that GP gives you with the Patty ARF. It is strong enough for the BME50cc engine with no problem. Some guys swap them out for a metal motor mount, but it's really not necessary and just another expense. Also, thanks, keep your installations as clean and as simple as possible. Less to go wrong or break.

RcPilotJAE: I just received my BME50 yesterday & was trying to mount it to my Patty using the original GP engine mount, but with even mounting the engine at the end of the mount, I'm about 1/4" off from getting the 7" needed from the firewall to the prop washer (to clear the cowling). Should I get a different mount with longer arms or put a piece of 1/4" plywood behind the GP mount to give me the 1/4" needed. Also, any certain type of bolts needed for the engine mount to the firewall?

Thanks---JC

JC:

I just measured mine to be sure, and I also came out at 6 3/4 inches. Don't worry about that 1/4 inch (I didn't, obviously) as the cowl can be adjusted so it's not a problem. (IE: just move the cowl back a 1/4 inch.) It's not enough to cause any problems with the cowl and you'll probably also find it tends to fit a bit better because you have that 1/4 inch of play. If you feel differently, use plywood, but you really don't need it.

The hex bolts and blind nuts they provide in the kit are fine for mounting the motor mount to the firewall. (Look at close up of engine picture in other post.) I did find on my 2nd Patty they didn't put the engine mounting bolts, washers and locknuts they did in the first one I had. If this is the case with yours, go to your local hardware store (better, Home Depot) and buy a set of 8-32 x 1&1/4 inch bolts. They come with hex nuts, but don't use them. While your there buy a package of 8-32 Nylon Insert Locknuts, use them instead. That way you don't have to worry about them vibrating lose. Use these to mount the BME to the plastic mount. (Again, refer to the close up picture. You can see clearly where these go.) I believe the washers are #8's. There are extra in the kit. Do use blue locktight on the bolts holding the mount to the firewall with the blind nuts.

I'm finishing my work on the engine today (hopefully) and as soon as I put the cowl back on I'll snap some pictures so you can see how to cut the cowl out. One thing I thought of though, was what muffler are you using? I'm using the Pitts style and not the stock one. That will make a big difference when cutting the cowl out. If your not using the Pitts, then I'm sure I've seen pix here somewhere of the cowl cut out with the stock (or standard) muffler, so don't panic..I'll find them and get them to you.

rcPilotJAE: Thanks! I really appreciate your help! As far as the engine ignition upgrade on the wires, did you get your's from CH. Is it a big deal to change out the wires & plug cap?

Separate question about hinges---did you use CA hinges or another kind? I think if I cut 1 1/2" hinges for the elev/rudder that should work----your thoughts?

JC[:-]

rcPilotJAE: I forgot to ask---did you use the same engine mount template for the glow engine? I did & it seems to have the engine slightly to one side. I had all marks aligned, but still seem alittle to one side. Will that make a difference?

Thanks--JC

JC:

I see you found one of the other 'Patty' threads. The metal H9 mount is a good choice, but here's the difference and it's one of your questions. With the H9 metal mount you can't use the glow template that comes with the manual. You'll have to do all the math over again. Quite the pain (not to mention waiting for the part to show up, extra expense, etc).

Question #1- Yes, you can use the glow template that comes with the manual. Yes, it looks off, because it is. Why? Look at the motor box, you'll see that the right thrust is already built into it. (One side is longer than the other.) The reason then why your seeing that it looks off is for the difference in the thrust line. Great Planes made it easy for you with the template and did the math. If you use their mount, use their template. It will come out correctly. If it was straight, the cowl wouldn't fit as the cowl also was molded with the offset in mind. With the metal mount your going to have to do the math over again to find the right thrust line so when it's mounted it will match the cowl.
This has to be done with the larger models (33% 35% 40%, etc). Because of the different engines used, and mounting techniques it's up to the builder to figure degree off set, thrust line etc to get it right. Since the BME is one of the only gas engines that can be mounted like a glow engine, your in luck! If you would have bough the DA50 for instance, you'd be doing the math right now.

Question #2 - Yes, I used the CA hinges. I cut them bigger (you can buy more hinge material at your LHS). If installed properly the CA hinges will never come out or loosen up. Since you've been in the hobby for 20 years, you should know this. Yes, other guys/gals use plastic hinges, or hinge points, etc, but the CA ones are fine for this size plane. Trust me one this one, I've put my Patty's through some very extreme maneuvers with lots of G forces. Never had a problem.

Question #3 - (Just realized I'm going back wards in the order the questions where asked..) Any way...It's not a big deal, just another expense. The Bosch cap and wire is about $22, the newer hall sensor is about $10, labor & shipping, figure another $15. CH will do the mods and have it turned around in under 2 weeks (from time you send it to the time you receive it back), but your going to spend a little under fifty bucks. I would wait and see if you have any RFI problems first before making the upgrades. (Save the money for now.)

I know this is your first gasser and you want everything perfect. I don't blame you one bit. But think about this, if you start changing a lot of things (IE: new motor mount, new upgrades to the ignition, different hinges, etc, etc.) after awhile this is going to add up and your going to find you just spent another couple hundred bucks! The only reason I had the upgrades done to my ignition was because I had a RFI problem. You may not. When wiring everything together in the plane, this is where you want to be critical and do things by the book so RFI or any thing else doesn't rear it's ugly head. All I'm suggesting is to see how things work out before you shell out more money for something that might not need fixing. (If it works, don't fix it!) We've all heard that one :-) But keep asking the questions, it's the only way your going to find out what's right and what's wrong when putting together a gas plane. Every one has different opinions, they are all good. It just depends (I guess) on how much your willing to pay.
Not to mention we all love toys (or we wouldn't be in this hobby). I have over $4K in my 33% Edge. Most of it is unnecessary, but I listened and read and got carried away. I now know when to stop and see that sometimes we don't need all the bells & whistles to have a great flying plane. Keep the questions coming!

My whole carb sticks out of the cowl on my Giant Stinger and I've never had a problem. I do run a velocity stack though. If your diaphram is pointed directly forward, you will need to block it from the air, or use the vent tube trick.

rcpilotjae, do you know where the fourth (ground?) wire attaches on the box end? I would like to do this mod myself.
Thanks,
Floater.

Floater-

Yes, it goes to ground. You could take it from the engine ground, twist it up with the rest of the wires and terminate it at the box itself, one of the screws will do (metal box-ground) or to the other end of the black ground wire. You'll have two black wires when done, both ground. I believe all it does is provide shielding to the main three wires coming off the hall sensor.