Author Topic: .61 Engine for D speed (Read 5749 times)

john ohnimus · « **on:** September 06, 2015, 03:59:54 PM »

I picked up a speed pan on the Bay and I have a HP .61 that will fit it in it. Anybody think this would work?? Not really looking to build a Nats machine but something nostalgic and to have fun with.

john e. holliday · « **Reply #1 on:** September 06, 2015, 06:52:56 PM »

That should work for going fast.

bob whitney · « **Reply #2 on:** September 08, 2015, 04:15:36 PM »

John, build a dizzy boy ,top cat or a wisnewski d ship ,dont over rev it and it should be a fun ship to fly

john ohnimus · « **Reply #3 on:** September 09, 2015, 11:00:23 AM »

Any ideas for venturi size on this engine? The O.D. of the opening for the carb/venturi is smallish. The Super Tigre .60's have a much larger port say 14mm or a bit larger. Also on this paticular engine the boss where the carb mounts is cast as though it could be drilled for a "sprinkler" type spraybar. has anyone seen this done on this engine?

bob whitney · « **Reply #4 on:** September 09, 2015, 11:33:10 AM »

if u are going to use a pressure tank or abladder u coud go with a rear needle and just run a tube to the venturi

john ohnimus · « **Reply #5 on:** September 10, 2015, 11:31:37 AM »

I was kinda thinking along thos same lines Bob. That would be a bit easier to fab up I think. Also keep my fingers away from that pesky prop!! I wonder if it needs to be a true venturi or if a straight piece of tubing would work as well. And i was thinking of a pressure fuel system. I read an article on CLspeed.com about an LA .25 they modded for speed and they didnt even have the tubing in place. Just the hole in the crankcase casting with the spraybar epoxied in place. Like I said not sure what is correct. Please see attached pic.

Bob Heywood · « **Reply #6 on:** September 10, 2015, 06:56:59 PM »

With a pressure feed fuel supply a venturi is not necessary. The attached pics show the Fox 29R "Bathtub" intake circa late 1950s. It worked just fine. The last Fox .36 Combat also used the same fuel delivery system. The fitting on the intake was just a simple barb to hold the fuel line.

Motorman · « **Reply #7 on:** September 11, 2015, 07:48:09 AM »

John, the only concern is prop blast blowing fuel out of the venturi. If your cowling is a good fit it will help. The farther down the hole you can get the fuel discharge the better.

MM

john ohnimus · « **Reply #8 on:** September 12, 2015, 11:09:51 AM »

I agree Motorman. The venturi that is pictured is not the one I wll use. I plan on making one out of delrin as the phenolic cracks easily. Probably will be around an inch long or so. Also I am going to drill the case for the fuel nozzle/spray bar assy. Any suggestions on prop size...??

Motorman · « **Reply #9 on:** September 12, 2015, 12:15:44 PM »

If that were my engine I would drill the frontcase for the spraybar then take a 3/32" rotary burr and put a notch on the bottom side of the oval cut out on the inside of the venturi bore so you can direct the spraybay discharge even lower. Then I would make a venturi from 7075 T-6 aluminum with a wall thickness of .025" and notch it so the spraybar holds it in and also use light pressure and loctite on the keeper screw. The venturi above the case can be thicker for a nice bell mouth shape. A height of about 1/2" above the case would be fine.

I would also cut that pan for a half pan set up so I could make the fuselage longer and make a good sized wing.

MM

john ohnimus · « **Reply #10 on:** September 12, 2015, 06:11:30 PM »

Alright I think I'm picking up what your Putin' down on drilling the front case. The half pan thing though... Is there a particular plan that would show me this. Remember the intent of this is to have some fun. Not an all out NAt's winning machine. I was looking at the TOP C.A.T. plan for this build. As someone had suggested. Two line control system etc.

Motorman · « **Reply #11 on:** September 12, 2015, 10:09:19 PM »

The Neddy Morris Indy D is a good plane. I'm assuming you're going to leave the cylinder/venturi exposed so you don't have to cut off the exhaust.

Have you ever made a speed ship before? Pay careful attention to the strength between the pan tie downs and the bellcrank mount. That engine will get you up over 150 MPH.

MM

john ohnimus · « **Reply #12 on:** September 14, 2015, 08:09:19 AM »

Motorman,

I really dont mind modifing the engine if need be, never built a spee model before. I have a pretty god idea on what needs to happen as far as tying the pan mounts, and bellcrank mount together. I am going to jig the pan up for

the drilling operation soon, (I have to get through the Stunt Season 1st) I alsoo need to relieve the pan slightly for the engine case. Still have to figure out what size prop to start with.

I appreciate all of the advice.

Tony O.

Ken Burdick · « **Reply #13 on:** September 14, 2015, 11:49:14 AM »

John.
Are you going with a 2 line on your speedster? If mono line you can get a good safe torque unit from Martin Higgs. If you are going to use 2 line, be sure you have an adequate bell crank and good button connectors. If you do not have this, you can also get them from Marty.
ukiespeedman@hotmail.com

This is "the fast Hippy" you may have read about. He would be a good resource for some of your questions. The guys are straight with you. The engine will run around 145-160 mph. Not real fast but it will pull a lot because of the weight.

A kid once asked me how old he needed to be for fly D speed......I asked him why he wanted to fly that event? He thought for a minuet then said...."they're just soooo cool!"

Good luck

Ken

john ohnimus · « **Reply #14 on:** September 14, 2015, 01:02:32 PM »

Thanks Ken,

Probably a two line unit. Just something to have some fun with. I have been interested in Speed since I attended the Nat's in '91 and watched those fella's get with it. I think they went 205+ that year.

Thanks for the info.

Tony O.

bob whitney · « **Reply #15 on:** September 14, 2015, 04:06:52 PM »

be sure to add some tip weight especially if u are going to use the AMA mandated cables

Ken Burdick · « **Reply #16 on:** September 15, 2015, 09:46:25 AM »

If you are going to build Ned's design, be sure to take safety precautions when laminating the wing using CA. Wear a mask and all that stuff as there is a lot of it involved. The wings are very strong and light. The airplane flies great.

bob whitney · « **Reply #17 on:** September 15, 2015, 11:35:28 AM »

i have flown Neds ship at 196 MPH and it dose fly good but if u are going to do 2 line i would give it a little more wing area to support the lines

john ohnimus · « **Reply #18 on:** September 22, 2015, 11:54:46 AM »

Thanks again for all of the advice. I have reached out to Marty and I'm sure we will do business, he sure does make nice stuff!!

Ken Burdick · « **Reply #19 on:** September 22, 2015, 02:30:00 PM »

yah, he's "The fast Hippie"
Going to be running his Frankenstein series of engine next weekend in Salem Oregon for Geezer speed aka N.W. B proto. Believe it or not, I clocked it at 115 after break in on an F2D wing. It was flying a little high, but that's just plain honking for a stunt motor.
Frankenstein will be published after the contest.

Egor

john ohnimus · « **Reply #20 on:** October 16, 2015, 07:58:35 PM »

The next installment is here!!! I worked on the .60 ship this evening and have made some progress.

john ohnimus · « **Reply #21 on:** October 16, 2015, 07:59:11 PM »

Another pic

C.T. Schaefer · « **Reply #22 on:** October 17, 2015, 06:44:51 AM »

Have you run the engine on a bench yet?

Ken Burdick · « **Reply #23 on:** October 17, 2015, 06:37:25 PM »

looks good! Keep this pix coming.

john ohnimus · « **Reply #24 on:** October 18, 2015, 09:27:50 AM »

I have run it on the stand. When I first got the engine I ran it with the R/C carb and it was very strong.