RCU Forums - Search Results
RCU Forums

Go Back  RCU Forums > Search Forums
Reload this Page >

Search Results

Register
FAQ
Community
Calendar
Today's Posts
Search
Vendor Directory
Notices
 
Page 1 of 2
1
2
Search: Posts Made By: Sport_Pilot
Showing results 1 to 25 of 42
Search took 0.09 seconds.
Forum: Glow Engines
08-04-2007, 08:33 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

I did not mean to get into specifics about efficiency. The subject is not about just two stroke engines, but I don't think the four stroke engines ar more then a few percent efficient thant the two...
Forum: Glow Engines
08-02-2007, 09:16 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

It actually varies with temperture, but 500 is a nice round number.



We cannot get that number because we must run it rich, I rounded to about 8000 for a fairly rich mixture.


A...
Forum: Glow Engines
08-01-2007, 07:46 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

No he did not hit the nail on the head. The heat of evaporation is only 500 BTU/lb and even at the proper rich setting we should get over 8,000 BTU per pound for the heat of combustion, so under...
Forum: Glow Engines
07-30-2007, 04:26 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Stay on topic please. Your post was wrong because you did not discuss the topic. This has nothing to do with baffling. This is about running a smaller higher picthed prop to help cool the engine...
Forum: Glow Engines
07-30-2007, 04:21 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

I don't know about 100's of degrees hotter, it depends on the timing and nitro content I think. A hot plug with high nitro may indeed be over 100 degrees hotter when 500 RPM lean vs 500 RPM rich. ...
Forum: Glow Engines
07-30-2007, 11:24 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

I believe I said much the same thing. The hovering plane that overheats is doing so mostly because the engine is runing leaner. This causes the fuel to run closer to the perfect mixture, and may...
Forum: Glow Engines
07-30-2007, 11:18 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Yallaair's tests shows that a higher pitched prop of the same approximate load improves cooling fairly signifcantly. Your test proved that the engine runs cooler when run very rich. The latter does...
Forum: Glow Engines
07-30-2007, 11:09 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Yallaair's test results shows that more air does provide more cooling. Higher airspeed will provide more cooling till friction is high enough to produce sufficient heat. Good baffling is a plus,...
Forum: Glow Engines
07-30-2007, 09:43 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

That would be incorrect. The fuel burned is a source of heat. Running rich may keep this heat down or reduce it such that only radiant heat is needed. But when operating normally it is mostly air...
Forum: Glow Engines
07-28-2007, 01:45 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Jazzy,
You are correct that power is the rate or speed that work is done, I do make mistakes from time to time. But my point was that the engine will make more power and heat at full speed. You...
Forum: Glow Engines
07-25-2007, 11:13 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Greg,
A very good explaination. Better than my poor attempt.
Forum: Glow Engines
07-25-2007, 11:11 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

The APC 13x8 and 12x8 tests show that the higher prop wash does indeed cool the engine better despite the fact that the engine is producing more power. But the engine is not poducing as much power...
Forum: Glow Engines
07-25-2007, 11:06 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Work and power are the same. Power is a means of measuring work. Load is simply the amount of force that is applied to the engine. On a dynomometer a force is applied to load the engine and slow...
Forum: Glow Engines
07-24-2007, 08:37 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

I agree, but also you mention work. Load and work are not the same thing. In a hover you are likely turning a prop at lower speed near the maximum torque of the engine, it likely has a higher max...
Forum: Glow Engines
02-20-2007, 11:31 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Well if most participating in this thread are present during the engine test, [sm=redface.gif]this could indeed be a factor. Something I did not consider.
Forum: Glow Engines
02-20-2007, 10:57 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

.


This has been discussed; you have to go supersonic for friction to be significant.
Forum: Glow Engines
02-20-2007, 09:56 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Flying people, or frying people?
Forum: Glow Engines
02-20-2007, 09:54 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Which it always is, unless totally wrong.
Forum: Glow Engines
02-20-2007, 09:40 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Neither are correct. Both are measuring surface temperature. Any device should be completly surrounded by the medium measured. Of course the infrared measures the surface temp, but only indrectly.
Forum: Glow Engines
02-20-2007, 09:36 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Yes I agree if you use the proper compensating thermocouple thermometer, not just a voltmeter you are correct, and just a voltmeter will give you incorrect readings. However you never addressed the...
Forum: Glow Engines
02-20-2007, 09:30 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Actually this has little to do with why fast moving air cools better. If you have more moving air you have more mass. If you heat one pound of water one hundred degrees or 100 pounds of water one...
Forum: Glow Engines
02-20-2007, 09:20 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Not sure how the Byron setup works on the bench VS on the jet, but I assume that this is because the suction is not ducted on the bench. If the air is ducted it would not matter if the engine is on...
Forum: Glow Engines
02-20-2007, 09:07 AM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

Only if at least part of it is completely in the element to be measured. Nothing can compensate for partial contact with ambiant air on one side and the measured substance on the other. Especially...
Forum: Glow Engines
02-18-2007, 10:19 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

At least I can agree with that!;)
Forum: Glow Engines
02-18-2007, 10:16 PM
Replies: 193
Views: 12,100
Posted By Sport_Pilot

RE: Prop pitch cooling - the final word

No prize, but if he did not convince the armchair mechanic, he did not accomplish his goal.
Showing results 1 to 25 of 42
 
Page 1 of 2
1
2


 
Forum Jump

Contact Us - Manage Preferences - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.