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Nose weight??

K

Koelemon68

Member
I have a RV 7 with a O-320, Catto FP prop 3 blade. With this setup, it has a 20# weight on the front of the crush plate for CG. I would like to get rid of the spinning 20# weight. What are options for getting more weight up front as a switch to a O-360 is not really a option. Battery is on the firewall.
 
Some options would be to change to a constant speed prop, FP metal prop, use an old Prestolite starter (you didn't mention what is on it now).
 
RV7 To Go said:
Some options would be to change to a constant speed prop, FP metal prop, use an old Prestolite starter (you didn't mention what is on it now).
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Additional options - change out Denso based alternator for heavier Delco or similar one (space permitting), lay in additional fiberglass/flox layers to front areas in your cowl, bolt on lead weight to firewall, change out your newer avionics for old King radios😵‍💫.
 
Thanks most of these options have been explored of done. I do have the heavier starter but cannot do the bigger alternator. I was looking at doing a CS prop and that would really solve all my problems but not cost effective at this time.
 
The 20 pound weight in front of the crush plate is the best thing you can do for C. G. adjustment.
The side benefit is a small amount of additional rotational inertia which can help with a smoother and potentially slightly slower (which is always a good thing on an airplane like an RV with a highly pitched propeller) idle speed.

Do you have any particular concern about having the weight mounted on the front?
 
rvbuilder2002 said:
The 20 pound weight in front of the crush plate is the best thing you can do for C. G. adjustment.
The side benefit is a small amount of additional rotational inertia which can help with a smoother and potentially slightly slower (which is always a good thing on an airplane like an RV with a highly pitched propeller) idle speed.

Do you have any particular concern about having the weight mounted on the front?
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no real big concern but just never seen anything like this as all my experience is working on certified aircraft. So I guess I am just not comfortable with a 20# weight spinning on the front of my engine. Also in engineering to get the same effect of the 20# weight where it currently is I have to add ____pounds for every inch it moves aft. I cannot remember the exact formula without looking it up. Honestly I will probably look into a CS prop in the future if I decide to keep this airplane long term. Problem solved.
 
Koelemon68 said:
Honestly I will probably look into a CS prop in the future if I decide to keep this airplane long term. Problem solved.
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First be sure that your engine is compatible with a hydraulic C/S prop. Many O-320s are not. What model is your engine.

As Scott says, the 20# crush plate is really a good option.
 
MT makes a nice electric prop that fits the 0-320. I have flown behind them and they work just fine. Not as heavy as a hartzell aluminum prop, but heavier than a FP.
 
A well balanced 20 pound crush plate is a good thing. The heavy rotational mass ie heavier flywheel helps to better dampen out vibrations and when your running at RPM it helps smooth things out.

In the automotive world they like the lightweight flywheel for the ability to rev the engine higher faster. If it helps your CG, I say leave it alone.
 
I'm running a 15# crush plate on the front of my RV9 O320 D2J and yes the asseccory case has the added fuel pump. The crush plate was added about 8 years after first flight and improved landings tremendously by moving the CG off the rear limit. Was not possible to land 3 point loaded and min fuel, the tail would touch first. Big improvement in landing config with that. I also did not wish to add that 15# with the 2 1/4 spacer using the long prop bolts required. I changed to a 2 1/2 prop extension ie spool piece bolted to prop flange separately and also bolted thru prop with shorter bolts. Saber mfg help me decide this and provided the prop extension.
 
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