Interesting New Project Thought
03-07-2011, 01:35 PM
#1
Thread Starter
Interesting New Project Thought
I'm wanting a Sopwith Camel but I would like the engine to run like the original - except for the engine spinning around the crankshaft part. But from what I've read and seen in videos, the Sopwith had an ignition interrupted speed control. No throttle in other words. To control RPM, the pilot would use a selector switch that would cut ignition to certain cylinders fro takeoff and landing.
Well, I would like to simulate that with an ignition interrupter on a 2-stroke gas. The engine would basically be set at WOT all of the time but you would control RPM interrupting ignition. I am an electronics hobbiest and I can create and program a PIC controlled circuit that would sit between the HAL sensor and ignition module. The circuit would monitor engine RPM and based on throttle input would let the the ignition fire more as more speed is required. Would that wash the rings out of a 2-stroke running it part throttle for an extended period of time?
Well, I would like to simulate that with an ignition interrupter on a 2-stroke gas. The engine would basically be set at WOT all of the time but you would control RPM interrupting ignition. I am an electronics hobbiest and I can create and program a PIC controlled circuit that would sit between the HAL sensor and ignition module. The circuit would monitor engine RPM and based on throttle input would let the the ignition fire more as more speed is required. Would that wash the rings out of a 2-stroke running it part throttle for an extended period of time?
03-07-2011, 02:07 PM
#2
RE: Interesting New Project Thought
ORIGINAL: SpinnerRow
I'm wanting a Sopwith Camel but I would like the engine to run like the original - except for the engine spinning around the crankshaft part. But from what I've read and seen in videos, the Sopwith had an ignition interrupted speed control. No throttle in other words. To control RPM, the pilot would use a selector switch that would cut ignition to certain cylinders fro takeoff and landing.
Well, I would like to simulate that with an ignition interrupter on a 2-stroke gas. The engine would basically be set at WOT all of the time but you would control RPM interrupting ignition. I am an electronics hobbiest and I can create and program a PIC controlled circuit that would sit between the HAL sensor and ignition module. The circuit would monitor engine RPM and based on throttle input would let the the ignition fire more as more speed is required. Would that wash the rings out of a 2-stroke running it part throttle for an extended period of time?
I'm wanting a Sopwith Camel but I would like the engine to run like the original - except for the engine spinning around the crankshaft part. But from what I've read and seen in videos, the Sopwith had an ignition interrupted speed control. No throttle in other words. To control RPM, the pilot would use a selector switch that would cut ignition to certain cylinders fro takeoff and landing.
Well, I would like to simulate that with an ignition interrupter on a 2-stroke gas. The engine would basically be set at WOT all of the time but you would control RPM interrupting ignition. I am an electronics hobbiest and I can create and program a PIC controlled circuit that would sit between the HAL sensor and ignition module. The circuit would monitor engine RPM and based on throttle input would let the the ignition fire more as more speed is required. Would that wash the rings out of a 2-stroke running it part throttle for an extended period of time?
One, your engine will continue to pull fuel through the carburetor, leaving unburnt fuel in the cylinder. Attempting to relight might work, but my expectation would be for the plug to be wet. That alone might be enough to stop the prop.
Two, your small single cylinder engine would keep spinning only on the inertia of the prop and crankshaft, unlike the rotary engine. I believe you're referring to the engine that has the crankshaft bolted to the firewall and the prop bolted to the engine case. That case has a lot of inertia with which to keep the prop spinning, between missed ignitions.
So, try it on a test stand first, and let us know what happens!
Best wishes,
Dave Olson
03-07-2011, 02:10 PM
#3
Thread Starter
RE: Interesting New Project Thought
Yea, there would be a lot of test stand activity for sure and I would think I'd need a heavy prop - something like an 18x6 or 19x5 for a DLE 20.
I wonder if it would cause it to back fire. That is my main concern.
I wonder if it would cause it to back fire. That is my main concern.
03-07-2011, 06:22 PM
#6
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RE: Interesting New Project Thought
A full scale prop will continue to windmill with the engine shut down, even at fairly low airspeeds. A small model prop will quickly come to a full stop even at fairly high airspeeds. Even larger model props on the 100cc and above engines do not windmill very long after the engine goes dead. I really don't believe that backfires or hydraulic locks will be your problem as the prop will quickly stop turning with the ignition off ... then you will be looking for a place to land.
03-07-2011, 07:10 PM
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RE: Interesting New Project Thought
OK so try the other side of the engine.
Think of 2 tubes slotted and one inside the other. Rotate one so that you would have a variable outlet muffler. Hook it up to a small motor gearbox and control the speed of the rotating cylinder. This might give you an interrupted engine sound. Especially if the rotating cylinder did NOT run at engine speed.
Think of 2 tubes slotted and one inside the other. Rotate one so that you would have a variable outlet muffler. Hook it up to a small motor gearbox and control the speed of the rotating cylinder. This might give you an interrupted engine sound. Especially if the rotating cylinder did NOT run at engine speed.
03-07-2011, 07:50 PM
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RE: Interesting New Project Thought
If you have a lot of money you can get a scale Bentley radial, runs exactly the full size original...Made by Paul Knapp of Rimfire spark plugs...One has been flown in a large bipe...Might be a video on youtube, Bentley radial....
03-08-2011, 05:16 AM
#12
Thread Starter
RE: Interesting New Project Thought
ORIGINAL: Tired Old Man
Will the expense be worth the reward?
Will the expense be worth the reward?
