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RV-3 with 0-290 speeds

C

Cuban8

Well Known Member
Patron
Hi All,

I Just picked up an RV-3 with a 0-290 (N20647). Kind of have the sickness now with 2 RV’s. The former owner/builder installed VG’s on it and it has a mid pitch Catto 2 blade prop. While I like the slow flight aspects of the VG’s I am pondering what the cost of these is to the cruise speed. Anyone out there with a similar config but without the VG’s? I would be interested to know what type of speeds you see.

Thanks
 
Hard to quantify

As the air thins out/density altitude increases, the effects and penalties of VGs also decrease. Measurable effects? Probably as nothing is free; however, those that I personally know that utilize them on something other than STOL-ish aircraft claim no noticeable effects when they are cruising up high; above 9K or so.

How are you intending to utilize the aircraft? You stated another RV so you probably already have decent cruise speeds there. Is the prop also pitched for climb? You could have a different kind of fun with this one. There's no right answer here. Get lots of opinions and go play with it.
 
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RV3 w/290 speeds

I have a mid pitch prop. It’s neither a climb nor cruise but rather somewhere in between. My RV4 is much faster but it’s got the 260hp 0-320.
 
Not on the RV-3, but Nigel Speedy did some extensive flight testing on his RV-8 to identify the effect of VG's on several different performance parameters. One thing he did not test was the chordwise location of the VG's.

On his RV-8 the wing VG's reduced the cruise speed by approximately 4 KTAS (The table below shows 5 KTAS, but 1 KTAS was due to the VG's installed on the underside of the horizontal stab). I believe the RV-3 and the RV-8 have the same airfoil, but someone more knowledgeable can chime in and correct me.

KitPlanes article--> https://www.kitplanes.com/vortex-generators-on-an-rv-8/

i-szM9RQv-M.jpg
 
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Thanks for this. Since the cruise difference is likely minimal and removing them will require some paint work I will likely just leave these alone for now. This is my 2nd RV3 and I do feel that this one has a bit lower landing speeds and slow flight characteristics.
 
James,

It should be noted that Nigel's speed without the VG's was 187 KTAS.

With O-290 power, the effect of the VG's should be much less than 3%.
 
That’s what I thought also. Appreciate you bringing this to my attention.

Thanks
James
 
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