enginehistory.org

[mhamer]

What is the best way to set up a prop on a running display.

Should it be locked and at what angle?

I prefer to have the governor on the engine and have the blades fully functional, to prevent overreving, and creating more wind. The blades will be about 5ft long. I won’t use the feathering feature. I have a electrically operated governor from a CV 440 but I need one that can be manually operated. Any recommendations on what governor would be a good fit?

I also need a 24v fuel boost pump TF 3900-2 or equivalent, fuel shutoff valve
WE 459-1 1/4d

Thanks

[jwilcox]

Hi, I have the R2600 which I run at several shows each summer. It has the 23e50 hub and blades from a DC3 cut to just under 7ft diameter. I have a working prop governor but never use it, I've found that 2200 rpm is lots for a demo, have had it to 2500+ rpm but really no need. My blades are set at the standard low pitch setting which moves a lot of air. Not sure if you are thinking 5ft in diameter or 5ft blades. I've found that with the 7ft prop I have to restrict the throttle movement to about 1/4 of the normal travel, if the throttle was not restricted I could easily overspeed the engine surely to the point of failure, the smaller diameter prop just cannot load it up.
Jerry

[mhamer]

Hi, Thanks for the info.

Shouldn't your functioning governor regulate the pitch as to not overev the engine ?
My blades will be aprox 6 ft each. so i wondered if by just installing the governor (constant speed control assembly HS 5U18-1) by itself, (ie no controls) it should regulate the prop to about 2000rpm.
i think i have the oil transfer seal. i'll have to look..

still need the prop tools. do you have all the prop tools and installed your prop yourself?

in case i go the No constant speed drive way, do you put a plate , gasket and
oil transfer nut inside the prop shaft ?

[jwilcox]

When I was much younger I worked on Avengers with the R2600, we would ground run these prior to the spray/waterbomber season to full power, 2600rpm and 49in MP. To do this the aircraft was tied to a very large concrete slab with more tie down stuff buried beneath. If the runup area was not clean the prop would pick up anything nearby including stones as big as a golf ball. My point here is these engines at full power,while amazing, are huge dangerous beasts, my 2600 in a 4 minute run averages 2gallons of avgas. Doing some comparison to other engines I think I'm making about 450 - 500 HP which is 1/4 of the full power rating. Anyone who says they run these on a trailer at full power just does not understand how it works, they can easily get full rpm but full power is another story.
All engine/prop combinations I'm familiar with are designed to allow the prop to control rpm within limits set by the governor with blade angle being the only way to do it. Once you shorten the blades the equation changes and overspeed is a real possibility. If you do use blades in the 6ft range that will still be about 12.5 ft in diameter and probably not too much less than original but will also be very dangerous for a ground display. People just want to see and hear it run they don't care if it's making 2000hp knowing it can seems to be what counts.
Sorry for the rambling's on but I feel safety should be first on the list for showing these engines as the masterpieces they are. My 2600 is always a hit at any show I've attended
Your engine is a bit bigger but if you would like any info on my setup I have all the trailer drawings and info I can share.
Jerry
Re the prop tools, I do have a few but your stuff will be a larger size and doubt anything I have will fit. 50 vrs 60 spline.

[mhamer]

i understand the dangers. My goal is to make sure it's cooled appropriately.
but i thought it would also be nice to be able to exercise the propeller, that in itself is a nice piece of equipment.

I'll probably start with a 40 degree pitch. i never plan on running it past high idle. Just off idle warm up.

[jwilcox]

I didn't know what to expect cooling wise either, that's one reason I made my blades extend a fair bit past the diameter of the engine but still easy to transport and get in and out of my garage. I have all the cylinder baffles but decided to leave them off, makes it more open for interested folks, allows lots of airflow and I think cools quicker when shut down. I do not have an oil cooler and run with about 15 gals of oil in the tank. After a 4 - 5 minute run at 70F the tank will be warm but not hot, I have run it as long as 10 minutes with no heat issues. On real warm 85F or so days I do extend cooling times between runs.
I can only speak for the 2600 but it has a real noticeable sweet spot between 1800 and 2200 rpm, spectators even notice it and comment after runs. Suspect this is the cruise range in the airplane. Re the prop cycling I doubt you will get much if any action out of it lower than 15 - 1600 rpm, may be wrong but don't think they work well at lower speeds, someone who has worked on 2800s will know. Think my low pitch setting is something like 22 degrees, due to the inboard end having more twist it looks like more.
Jerry

[mhamer]

You only look at oil temp? I plan on installing cht bayonette probes on each cylinder. You think it cools better without baffles? My r2800 is off a convair that used the exhaust gas flow to suck in cold air for the cylinders. I wonder if baffles prevent cooling for the running display set up... I’ll look at CHT. Only way to know i guess is to test with and without baffles... quite a labor intensive experiment

[jwilcox]

Hi, Yes the only real temp indication I have is oil temp, as I stated I usually run 5 minutes or less, on worm days after 3 or 4 runs I will see the temps up in the green range but never gets hot. I considered using all the baffles just for authenticity and expect without them if I ran for longer times it would get hot/cold spots but running at a max of 25% power it does not produce nearly as much heat as it would at flight powers. The baffles are also meant to work at a couple of hundred mph airspeed so what they actually do taxing on the ground who knows. Easy these days to get a laser temp gun to use on your first runs to see what it's doing
My engine has been sleeping all winter, looking forward to waking it up in the next few weeks.

[mhamer]

Hi,
What size bolts do you use? My 2800 will be fully cantilevered/ suspended by the engine mount. My CV 440 engine mount has only 4 1/2in diameter bolts to bolt it to the frame... seems a bit small to me. I’d hate the have a bolt failure and destroying my motor in the process...
Thanks
Marc