A question about engine mounting..........

I have a question maybe someone can help me with. I am interested in mounting a side exhaust engine with the head in the position that allows the exhaust/muffler to be centered on the bottom of the airplanes fuse. If you mount an engine this way where do you center the fuel tank?

Thanks

Rick Henry

Frank Carlisle
proud member of R.C.C.D.

I think that's an easy one Rick. You'd set the tank up just like it was a profile model. Pick up tube centered on center of venturi with room to move the tank up or down a bit.

Good question. I have read of members here who test their tank height setup with a test stand...apparently it comes out fairly close. I believe Al Rabe was one of those using this method. The other answer is to eyeball it and allow for (plenty of) adjustment.

This would be a good time to try an R/C clunk tank of your choice. The tank may be moved, or the (fixed) uniflow pipe can be moved, or both, your choice. When you get it sorted, you should be able to come up with a guideline, but remember that it only applies to that one engine make & model. While a clunk tank is maybe less permanent...might need tweeking after a moderate crash landing, or after some preventative/necessary maintainance...they can be easily tweeked at the field, with minimal time spent. Tradeoffs. Steve

LAST EDITED ON Jun-07-06 AT 08:09 PM (CST)
 
Thanks for the info guys. I am getting started on a ARF Giles R/C (converted to CL stunt)3D plane the same one that Richard Oliver has posted about. I know the whole ARF/ARC thing is kind of a big controversy with a lot of the C/L Stunt guys but I just had to give it a try. The fuse is pretty wide and I cant decide between a ST 60, ST 51 or an ASP 53 Len reworked for me. It looks to me that the only way to make one of those engines work would be to mount it so that the exhaust is at the bottom of the fuse. If you mount the engine in the traditional inverted position the muffler would be right against the side of the cowling. Im also a little concerned about mounting a ST 60 in a plastic/nylon type RC mount.

Hayes RC mounts are not flimsy. If they will hold a YS.60 or a big block 4 cycle they can surely hold the power that a Super Tigre can make.

Rick,

I have seen the Giles 202 fly. It is a great flying plane .

Please not that Richard has posted pictures of his including the

motor mounts.

I think Frank is good on the answer --The Skywriter guys probably have the definitive answer on this.

Perhaps mr Doherty will check in on the question.

LAST EDITED ON Jun-09-06 AT 08:15 AM (CST)
 
Rick,

Before I try to answer your question I would like to know how you intend to construct the nose / engine mount as this will have some impact on how you will mount the tank.

If I read the question correctly, you will want the engine centre line at 225 degrees from vertical. You will also need to make sure that your fuselage is deep enough, wide enough and that the muffler projects far enough out to end up where you are thinking.

Whithout trying to throw water on a good idea, you would have a much easier time of it if you mounted your engine on its side as if in a profile. There is no running benefit other than that it hides the muffler.

Kim.

edited for spelling

LAST EDITED ON Jun-09-06 AT 10:08 AM (CST)
 
I've done several planes this way. I've always lined up my feed tube out of my clunk tank
with the centerline of the needle. Not nearly as easy as locating on
a profile or inverted engine, but have yet to be off.
Attached is a picture of my just finished Desperado with the
muffler exiting center of fuse.

Robert, That is exactly the configuration I was talking about. Your airplane is very nice. Thanks for the information and the photo.

LAST EDITED ON Jun-09-06 AT 03:21 PM (CST)
 
Kim,

The plane is a Giles 202 3D ARF. Its the same RC ARF that Richard Oliver has posted about. The problem I have is he (Mr. Oliver) is using a Ro Jett rear exhaust engine. I have the choice between a ST 51, ST 60 and one of Len's ASP/SSW 53's and the fuse is really wide compared to our standards in CL Stunt. With the engine mounted inverted I would have to have some type of spacer or extension between the exhaust port and the muffler because there just isnt enough room for the muffler to exit the side of the fuse/cowl. The airplane is designed to mount a 4 stroke engine inverted or a 2 cycle engine at an angle that allows the exhaust to exit the bottom of the fuse.

I just have never mounted a engine at that angle before and I wasnt sure about the tank location ect. The airplane seems to be pretty well built and uses a plastic/nylon engine mount like the ones commonly used by the RC guys. The firewall seems to be a double thickness plywood possibly about 1/4 in thick. It doesnt appear that any fiberglass cloth was used durring construction but the fuse is bulky so hopefully that in itself will offer some vibration dampering for a ST engine...I hope. It would look pretty cool with the engine mounted so that the exhaust comes out the bottom of the fuse if I could make it all work.

Again, thanks for all of the input guys. I am treading on unfamiliar grounds here and all the help is very much needed and appreciated.

A little progress on the Giles......

Guys I finally got a chance to work on the Giles ARF over the weekend. Things are moving slow but I got the center section of both wing halves cut out to accept a plywood spar with the bellcrank mount. I also got the adjustable leadout guide mounted and a tip weight box mounted. I'm just about ready to install the spar and bellcrank and join the wing halves. Then I can install the wing and move on. I'm still up in the air about which engine to use. I'm a little leary about the ST 60 just because I'm unsure if the nose structure is stiff enough. If anyone has any input please let me know.

Thanks,