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Tom, The supercharger housing has a 1” air bypass \ butterfly that allows airflow around the compressor. I use a vernier control cable to operate. Bobby From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Thomas Giddings
Sent: Monday, December 02, 2013 9:29 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Slow but steady progress Bobby: I am interested to know How did you Bypass the supercharger and how did you add boost? On Dec 2, 2013, at 5:35 PM, Bobby J. Hughes wrote:
Make sure your fuel pressure regulator is tracking 1:1 with boost pressure. That might explain your steep fuel curve.
For the first few flights I had the super charger bypass open during takeoff with less than 30” MP. I then started adding boost a pound or two at a time while circling the airport. Once comfortable with the tune I started using boost for takeoff and gradually increasing to 39” MP over several flights. What size waste gate do you have? From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Scott Emery
Sent: Monday, December 02, 2013 1:09 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Slow but steady progress Yes, I've done tethered power runs. I tie the plane to the trailer hitch on my pickup, in front of my hangar. I'm a big chicken, but I have run it up to 2200 propeller RPM which is about 4800 engine RPM. That is 'take off power" which I have held for several minutes at a time with no water or oil temp problems. In the past, with the previous turbocharger, the boost pressure from the turbo was too high, and only about 1/2 throttle = about 35" manifold pressure with about 50" from the turbo to the throttle. Now that the turbo is more appropriately sized, the pressure differential across the throttle is less, and a run away boost condition is less likely. Now a quick shot of throttle is very controllable and the reset of the EC-2 has worked, which indicates to me that I can ground run at higher power for a longer period. I don't think I will be able to take off at full throttle. I'll limit throttle to some RPM or manifold pressure. I think I could possibly overboost the programming limit of the EC-2 or overspeed the prop.
Sent from my iPhone Have you tried to tie it down a run it a full power for a minute or two?
(Well, at least at the minimum power estimated to take off and climb.)
Highly recommended before attempting any first flight.
Finn
On 11/29/2013 11:14 PM, shipchief@aol.com wrote: I got a chance to play with 89SE today, I've been running and tuning after all the tribulations of making right an improperly built engine with an improperly sized turbo. Today I re-read Tracy's manual for EC-2 & EM-3 and started/warmed the engine. Then I bit the bullet and returned to the EM-2 default setting (Mode 1 power up). Just like I had intended in my last letter. I tried auto tune with the EM-3, but I had a steep slope on the EM-3 correction table graph. so I had no way to establish a safe state of mixture beyond ground running conditions. Well it works a charm! I think it's flyable now. I taxied about and gunned it a few times. I feel a transition when injector staging occurs, and I could work on the low idle, but most of the taxi, run up and a brief blast of pre take off power all works well with the mixture knob at 12:00. So I feel confident that 89SE can fly when the weather improves, and I get the rest of the fairings on. I'll do some more tethered high power runs and take pictures of the EM-3 data page, and the dual manifold pressure gauge, then go home and make another RPM, Boost & fuel flow graph. I'm collecting intercooler bits, with the intent that I'll have everything together to install it on the engine, and fiberglass up the inlet duct and sealed air exit. The only way I could control heat on the engine water and oil was by having the inlets & outlets of the heat exchangers be separate from each other, so I plan this also for the intercooler.
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