Al ; I suppose there are some exceptions but most manual trans cars have a 40# flywheel driving an input shaft geared to a counter shaft, oil bathed in 80x90 wt. or ATF lube, auto trans cars have a 30# fluid filled torque converter driving a pressure pump drive-shaft, they need a load to keep things tight, a Lyc eng. with crankshaft counterbalance will come apart without a prop at low RPM, one of the reasons for slow smooth throttle movements. David R. Cook RV6A Rotary.
Kevin;
Curious, isn’t it? We all start our vehicles every day with no load, and never think a thing about. The first start of my 20B on the dyno was with no load, and the first start on the plane was without a prop. It idled fine at about 1200, and I could crack the throttle a bit and control the speed without a problem. So it depends.
Thing is; it’s bad to take risks if you don’t fully appreciate the risk you’re taking. If you don’t have an oversize throttle plate, and have positive control on throttle position, know your carb (or FI system), etc; go for it. Just recognize that with even small throttle opening there is potential for the engine to rev up very quickly.
As far as cooling; it might be just about as easy to rig a radiator and blower for cooling as the questionable setup of a 50 ga drum. With no load and low rpm it will generate very little heat; a household fan blowing on the radiator would likely be sufficient. And when you do get a load on it, go to your friendly furnace repair service a get a centrifugal blower for nothing. Of course you’ll also have to cool the oil. And for sure don’t run without proper instrumentation.
All that said – is there some reason to be in a big hurry to get this thing running?
FWIW;
Al G
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Tuesday, January 05, 2010 8:52 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: first start check list
Kevin,
I certainly would not start the engine without a load on it. Things don’t always go as planned and more than one person has scattered parts or burnt bearings by having the engine rev to destruction without a prop (or some kind of load). Make sure you have oil to the bearings. I would take off the oil line going back into the engine and crank engine until I see oil coming out before I would even think of starting it. Folks have reversed the Goes inna and Comes Outta connections on a remote oil filter – and no oil flows.
With an idle setting of 1600 rpm – if I take my prop off, the engine “idles” at 5000 + rpm. Crack the throttle plate just a bit more and you easily may have 8000 rpm (or much more)
Just not worth it in my opinion.
Yes, if all goes as planned you may have not problem – but, just bump the throttle cable or find the rev limiter not set up properly and you could ruin your engine.
Good Luck
Ed
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of kevin lane
Sent: Monday, January 04, 2010 11:59 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] first start check list
I am just about ready to try my first attempt at starting my renesis. for my first phase, at least, I've chosen to use a side draft Weber carb and DIS ignition system, which Lynn designed using an MSD ign box for the primaries and 2 Chrysler elec ign's for the trailing plugs. I thought I'd ask before introducing gasoline to my "creation" of any steps or checks I need to do first. the engine and mount are bolted to a mockup plywood firewall held up with steel legs. the psru is installed, as well as the radiators [oil & water]. exhaust is just headers for now [pointing down]. when I crank it over all the plugs are firing [especially the MSD powered ones, which fire multiple times below 1000rpm]. the carb is brand new, with whatever jets they come with. haven't designed a leaning capability yet.
1. I need to add a oil pressure gauge right away. I'll need water temp after it gets running for any length of time. put mineral oil in for initial break-in [turrentine engine, never run]
2. oh yeah, get it out of the basement! guess airport best for making lots of noise
4. got the 6k rpm limiter plugged in to the MSD
6. fabricate some remote throttle cable? or do you just stand there and manipulate it by hand?
guess I fine tune timing after it is running with a strobe light? I've marked the firing points on the flexwheel. the pick-ups can be adjusted some if needed.
I assume I don't need a prop or club at this point, right?
thought a small gravity fed fuel tank would work at first.
should I buy new plugs? the used ones that came with the engine seem to spark OK.
could I run this early on with the water pump attached to say a 50 gallon tank of cold water rather than trying to get it radiator cooled?
kevin [it won't be loud, will it? ☺]
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