Tim Wiltse-RCU

Well today was spent testing engines. One of mine and one for Steve. I had made a steel drum for the MK2 but it was a little lose fitting due to me machining it alittle off. Well needless to say it took me the better part of the day screwing with it before I took the time to make another drum from Delrin this time. Using very conservative intake timing it will turn an APC 4.5x4 at right around 17,000rpm. This was on an other than anodized stock Sure Start crankcase, cylinder/piston and head with one head gasket and 30% nitro. It was with a RR-1's crank with the extra "pin" on it. Tomorrow will be spent opening up the timing, using a trimmed piston and different prop combos. Also I will dig into making a fixture to drill the cranks to be able to press in a pin to drive the drum. Here is a VERY BAD video I made using my camera on my phone. DO NOT have the sound turned up it's really bad.

[link=http://www.youtube.com/watch?v=4FUBzFnQPaA]Sniper DR .049 Mk2 test run[/link]

LAter,
Tim

combatpigg

My Feedback: (3)

Keep at it, Tim, your work will payoff. Delrin is an interesting choice of material.

flyinrog

My Feedback: (1)

yep, looks good, sounds bad

ptulmer

My Feedback: (5)

The 4.5x4 prop is pretty big compared to the 4.2x4. How do those RPMs compare with a regular SS? I tell you Tim, that is one nice looking engine!

Tim Wiltse-RCU

Thanks for the comments guys! I was up and at em early this morning. I only changed the cylinder/piston set out for one that the piston had only been trimmed for SPI. I did not thin the piston wall on this one. Again I was running 30%nitro with 2 head gaskets. The APC 4.5x4 gave up 19,000rpm and the APC 4.2x4 turned out 20,000rpm. Timing was left the same as yesterday. I will try to get it mounted on a plane this afternoon and see how it does in the air because that is where is really counts after all![link=http://www.youtube.com/watch?v=V3Kn2WW-1xA]Sniper Mk2 with 4.5x4 prop[/link]

[link=http://www.youtube.com/watch?v=cd9tEgHHZQ4]Sniper Mk2 with 4.2x4 prop[/link]

Later,
Tim

Andrew

A beloved sound for this group, but I'll bet your neighbors were not as impressed.

Tim Wiltse-RCU

Suckers they all are working or something so no one else was home!

Later,Tim

flyswatter

Ditto Tim! You are going to have us standing in line for those little beauties!

Tim Wiltse-RCU

Well I spent alot of time today messing with making up some heads for the Turbo plugs. Even after reading Andy's work I made 3 using a center drill...and they sucked by sucking I mean leaked like crazy. I couldn't figure out why. The center drill is 60degrees just like the bottom of the turbo plug. I guess it really has to do with the length of the taper on it. Once I used the #3 philips bit it worked great this time without the LEAKS! Never would have thought you could drill with a screw driver bit..go figure. SO onto the engine it went and after messing with different gasket counts the best it will do is 19,600rpm with the APC 4.2x4. This is about 1,000rpm down from a stock head that gave 20,000 or so rpm yesterday. Is it worth it to us to lose 1,000 in exchange for being able to but $4.00 plugs at the LHS? The Galbreath/Nelson setup is the cats meow but you can't get the plug local. What do ya'll think?

LAter,
Tim

combatpigg

My Feedback: (3)

Tim, what does this P/L set baseline at on a KillerBee?

SGC

Tim,
What brand/heat range turbo plug did you use? maybe better from a different heat range plug. Also what head did you convert? maybe it needs some volume reduced to get the max out of the turbo plugs.
Stewart

Tim Wiltse-RCU

CP,

Good question! I'll try to stick it on a KB'ish backplate tomorrow, as well as a stock Sure Start backplate.

Stewart,

I hate to say I don't remember which plug I picked up at the LHS. I just asked for a "hot" turbo plug. I tosed the little package out before I thougt to write it down. Also I did the conversion on a stock low compression Cox glowhead. I can see that the hole for the element is bigger than the stocker. Next will be to convert a Norvel button.

LAter,
Tim

SGC

Tim,
Try doing a conversion on a SS head and mod it like ptulmer did to make a TD style head from a SS head, the reduced finning should help keep the heat in the glow plug.
Stewart
Heres the thread :- http://www.rcuniverse.com/forum/fb.asp?m=4608177
Stewart

combatpigg

My Feedback: (3)

The baseline comparison is important because the bar has been set pretty high by the reedies, plus you want to know if you're starting out with an outstanding P/L. A reed doesn't take any power for the engine to operate, but the airflow past that buzzing flat plate is less than ideal, or so it seems. On the other hand, the rotor valve takes power to turn, but it offers a better pathway for the air to take. The rotor must not allow crankcase pressure to escape, but it has to be friction free.......a pretty tall order! I think friction and complete sealing when the port is shut are the 2 biggest obstacles to overcome. I would think that the intake timing should be aboutthe same as the TD, but I don't know. If you were to contact Clarence Lee and tell him what you are trying to do, I'll bet he would get a kick out of helping you. He could save you lots of running around. The guys at Delphi Forums, like Glen Dye and Scott Newkirk also have lots of savy with RR engines. They bring up stuff like demagnitizing the crank to reduce drag from electromotive forces........[8D]

skaliwag

My Feedback: (1)

Just a thought... What about a " blower" like Dr. Ralph uses on his Radials? Its xxx long with Vanes and runs of the crank,

Tim Wiltse-RCU

It's funny CP I have been a member of the Delphi forum for years but have never been able to post there. I even signed up with a second name and same thing..weird. As for the rotor having a straighter air path it really isn't. Don't forget I am working with a drum rotor this time. The intake charge comes down the venturi and then has to take a 90degree turn down into the engine and then a 180degree turn up into the cylinder. I don't know though...heck 19/20,000rpm on a 4.2x4 without worries of dirt getting stuck in the reed and glow plugs you can get at any LHS I guess that's not so bad is it?
On the disk rotor version I used TeeDee timing and got the best numbers. I did make up a drum this morning and cut it to have "better" TeeDee'ish timing and didn't see ANY difference in output...I didn't expect that at all.

LAter,
Tim

combatpigg

My Feedback: (3)

Tim, those numbers show that the engine is holding its' own, but without a baseline reading..........all we can do is speculate. You are the one putting in the time, so all I can offer is my thoughts.
The blower idea has practical limits, I think the only way to show net gains with a 1/2A engine is with an electrically driven pump.

rainedave

My Feedback: (1)

Tim, I don't know much about the internal workings of engines. Could you post some pics of the drum rotor? Also, what type of induction did the Space Hopper and Sportsman use? Were they similar to what you are doing or totally different?

Thanks, David

Tim Wiltse-RCU

CP,

A mini NOS system would most likely be the best bet

Dave,

The Space Hopper and Sportsman are reedies. The RR-1 is drum rotor intake like I am playing with here.

LAter,
Tim

rainedave

My Feedback: (1)

Thanks, Tim.

combatpigg

My Feedback: (3)

Tim, I've thought about it, but you would need quite a little tank to maintain 900 PSI for 2 minutes! There are practical limits to alot of things. It is interesting to read 1950s HOTROD magazines to get inside the heads of what those guys thought the limits were. hind sight is 20/20, but it is funny to read about some of the old ideas. It is amazing to see how far we've come. I don't know a drum intake from a disc. The K&B 6.5 is a disc intake, that is the engine that Mr. Lee developed.

build light

Quote:
"Is it worth it to us to lose 1,000 in exchange for being able to but $4.00 plugs at the LHS?"

I believe the answer is yes to many. At least for general purpose use. If one decided to "hop up" the performance, a simple head switch with the greater cost would simply be a matter of choice as it would be for anyone who seeks to get higher performance with simple "bolt-on" parts.

I do not offer this opinion to let one think that experimentation would cease. This all sounds like a lot of fun and helps us to be more creative and demanding. Reaching for higher goals is always a good thing.

Keep up the good work! I love the work and discussion of this new endevour!

Robert

indoorff

My Feedback: (2)

Great work Tim, keep us posted! How bout some pics?

Chris

D Bronk

...I`m also uncertain ,about An RR.Is it a Rear rotary disc, similar to the Rotax Rotary Disc engine,that I posted pics of,spining a plate with a piece of pie missing?.A drum Rotary.? Do you mean, like a Crank inducted, type Deal ,like Norvels use..I too ,would like to see, a parts exploded, drawing , so that ,I can understand more,about what you`re doing...

..I`ve been thinking about these turbo heads too..When Andy said, he copied the exact angle ,of the plugs seat, to the head, he had a leak too.Now Tim ,is the second guy, on a different lathe ,ending up with a leak also..Tim try decreasing the angle(just a couple degrees), in the heads` seat.You`ll end up, with less of a contact point, between the 2 parts.But, by doing that ,you`ll generate ,a tighter, mechanical, seal.Sort of like, what generates more pressure(pounds per square inch),a hundred pounds sitting on a 45 gal. drum ,or a hundred pounds sitting, on a 1 gal. pail..I think,I mentioned to Andy, that you might have to custom Grind,a drill bit.But then again ,if a screwdriver bit works,why bother..

combatpigg

My Feedback: (3)

I think the angle of the plug face is supposed to be less than the plug seat in the head. The idea is to allow the plug to slightly burnish the seat as it meets it under force. Same idea as the way the valve and valve seat angles are done in a cylinder head.