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-   -   Low powered RV-4 (https://vansairforce.net/community/showthread.php?t=33354)

pierre smith 08-23-2008 06:15 AM

A little OT.....but...
 
Quote:

Originally Posted by allbee (Post 250267)
.............. I go into the mountains all the time and fly through the channels, very fun also. Don't know if I want to do those things with the RV, can't see straight down, no I don't think so. That's why I'm keeping the kitfox.

.....powerlines have claimed quite a few. From my Ag experience, if you're going to fly down a river or canyon, look left and right continuously, since the towers or power poles will show up and THEN you'll more easily find the powerlines in advance.

Be safe,

steveKs. 08-23-2008 06:30 AM

Buy a Cub.

Steve Sampson 08-23-2008 07:17 AM

It would be quick!
 
Quote:

Originally Posted by JDRhodes (Post 250065)
Just curious - .... What could you expect from <100HP?

I am still on my flight test here in the UK. All the testing is done so I am just building to a required 25hrs. I just spent a good half hour this morning burning about 5.5USG/hr. Not sure what power that is from a carburated 160hp O-320 but 2130rpm and 22.5". My guess is well less than 50% rated power but I will let you work that out. That gave me between 160 and 165 mph at around 3000'.

So in answer to your question it would perform quite well in level flight. However I think there would be two issues:
- resale value as others have mentioned.
- the CofG would be rather impractically far aft I suspect.

rocketbob 08-23-2008 08:49 AM

O320's can be found for cheap... Not too long ago I bought one for $2K.

Regards,
Bob

JDRhodes 08-25-2008 07:49 AM

Quote:

Originally Posted by N941WR (Post 250189)

PS. and build the -4 with an open cockpit option!


Is there such a thing? I've got pencil sketches of that, too!

N941WR 08-25-2008 08:54 AM

Quote:

Originally Posted by JDRhodes (Post 250829)
Is there such a thing? I've got pencil sketches of that, too!

Jeff,

Some time back someone posted a picture of an open cockpit RV-4 (I know there is an open cockpit RV-3 flying in Hawaii as well.) but I couldn't find it in a quick search.

The guy had it set up as convertible so he could put the bubble back on in the winter. In the summer he had two windshields. The rear one would be removable but I don't know if the front one remained in place when using the bubble canopy or not.

I suspect, but don't know, that he might limit his cruising speed to keep from getting pounded by the wind.

N941WR 08-25-2008 08:58 AM

Quote:

Originally Posted by RVjim (Post 250084)
Bob Each is building a RV-4. He hasn't decided on an engine yet. It's between a Cont. O-200 or a Lyc. 235. Bob is concerned that the Lyc. 235 will have to much power...

Jim,

It is my understanding that it is easier to put an inverted oil system on a Lycoming. If negative G's are important to him, this might impact his selection. Other than that, there is nothing wrong with the O-200. Well, other than he will have to build a custom engine mount for it. Yet another reason to go with the Lycoming.

Besides, too much power translates into a great climb rate with the proper prop.

iwannarv 08-25-2008 09:57 AM

throttle stop?
 
You could put a -320 on for good resale value, but fabricate a throttle stop, limiting you to only 2/3 throttle or so? Seems like something like a stop directly on the throttle might be easily removeable in case you do want to have all the power, but try to keep it on there to limit your hp and fuel burn. :cool:

Ron Lee 08-25-2008 07:12 PM

If fuel flow is that important put in a fuel flow gauge. Once you approach your limit don't advance the throttle more.

RVjim 08-27-2008 07:15 AM

aerobatic LSA-4
 
Quote:

Originally Posted by N941WR (Post 250852)
Jim,

It is my understanding that it is easier to put an inverted oil system on a Lycoming. If negative G's are important to him, this might impact his selection. Other than that, there is nothing wrong with the O-200. Well, other than he will have to build a custom engine mount for it. Yet another reason to go with the Lycoming.

Besides, too much power translates into a great climb rate with the proper prop.

Empty weight has been our primary concern. You point about using the Lycoming 235 engine with an inverted oil system brings up an interesting point related to aerobatics. The LSA gross weight limit of 1320 pounds is below the RV-4 maximum aerobatic weight of 1375 pounds.
Our current challenge is to have a high enough useful load to still be a two place aircraft. And the empty CG location plays a big part in this, also.
Maybe an inverted oil system will be required to keep the CG far enough forward. :-)

I heard recently that registering an existing homebuilt design as a LSA can increase the value of the homebuilt. However, this could have beed idle speculation, because of the current selling price of LSA's. Anyone know about this?

Regards,
Jim Ayers


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