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  #11  
Old 06-27-2018, 07:35 AM
Robert Anglin Robert Anglin is offline
 
Join Date: Mar 2008
Location: houston, texas
Posts: 868
Default Agreed!

Quote:
Originally Posted by f14av8r View Post
You can't get there, legally in a RV-4. I've owned a -4 and an -8. The RV-4 is just not a two-up aerobat. Cook the numbers however you like but it isn't. Your CG or your weight will be out of whack. Can you load your 200 lb neighbor up and go do loops? Sure. But, just because you can doesn't mean you should. You'll be so far out of CG, and probably overweight, that it will not be a comfortable experience.

The RV-8 is most certainly a two-up aerobat. Just manage the CG appropriately. Depending on the weight of the person in the back seat, you might want to add some weight up front. But, you'll definitely be within the weight limits and you'll be able to manage the CG.
I agree, with this and add that if you find an 8 or better build one that has a good weight and configuration for it you will be fine. We have an 8-A that is 1008 Lbs. with a Prince "P" tip wood and carbon fiber prop. We put it together with a strong IO-360, that puts out about 195 Hp. The airframe does have a "dash one" wing and the empty C.G. is close to the front of the limit. This set-up allows the aircraft to be used to its full potential for both seats. If you want to go out for a hour or so and do some fun flying with a friend you can just unload everything but for 16 or 20 gallons of fuel. Always watch your rear C.G. limit, it does change a little forward for Aero. Or if you want to do KOSH with the wife or friend, you load 50 Lbs. in the front baggage, 50+25 Lbs. in the rear baggage and shelf, Full fuel in the mains and anything that is left over in the seats and go. There is a lot of extra weight that does not need to be carried for those day trips. I would vote for the eight in this question. Just our two pennies. Yours, R.E.A. III # 80888
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  #12  
Old 06-27-2018, 10:34 AM
Reformed SeaSnake Reformed SeaSnake is offline
 
Join Date: Nov 2016
Location: Beaverton
Posts: 30
Default Keep looking

Quote:
Originally Posted by HansR View Post
Hi.
I have yet not decided whether to buy a second hand RV8 or RV4.

My main target is to have an aircraft able to do aerobatics with two fullgrown males onboard.

On spec, everything points towards RV8, but when I found a plane of interest, it was with the Mark1 wing, with max aerobatic weight 1500 lbs.
The empty weight is 1140 lbs, leaving just 360 lbs for useful load. Even with the new wing with 1600 lbs aero weight, it is just 460 lbs useful weight. Not much fuel if the crew is 400 lbs.

I checked the RV4. It seems to be 1375 lbs max aerobatic weight, and 930 lbs empty weight, giving a 445 lbs useful load.

As far as I can see, the two planes have about the same useful load, providing a low margin for fuel.

How do you do with your RV4/8? Do you fly aerobatics with passenger?

Does anyone know the design difference between new and old wing?

Do you exceed the max aerob. weight if you stay below 4G?

What other advantages do I get with a RV8 (except a bit more room in the cockpit and more baggage)?

I really want an aerobatic RV, and I would like it to be aerobatic also with passanger. Please help me with the arguments for the two models.
That is a fairly heavy 8. Look for one built a bit more recently with a parallel valve engine and composite or wood 2-blade prop and the weight should be under 1100. With the -1 wing, that gives you 400 lb for crew and 100 lb fuel. That should still give you 30-45 min of acro, 15 minutes to get back home and a 30 minute reserve. My Hangar neighbor competes in acro in a -4 and he never practices longer than 30 min at a time.

The difference between the 2 wings is the spars. The -1 spar is the same as is used in the 7/7A. Never asked Vans, but I'm sure it was to reduce tooling costs as much as anything. Max gross is the same (gear limited I think).
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Beaverton Oregon | RV-8A, Very slow QB
No Pithy quote here; just the sincere hope that your day ends better then it began
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  #13  
Old 06-28-2018, 01:44 AM
HansR HansR is offline
 
Join Date: Jun 2018
Location: Sweden
Posts: 16
Default

Quote:
Originally Posted by Saville View Post
I thought that, in general, Mark I wings on an -8 meant an aerobatic load of 1550lbs.
According to Mitchell Lock, president of Vans, the max aerobatic weight with the old wing is 1500lbs.
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  #14  
Old 06-28-2018, 01:52 AM
HansR HansR is offline
 
Join Date: Jun 2018
Location: Sweden
Posts: 16
Default

Quote:
Originally Posted by Reformed SeaSnake View Post
That is a fairly heavy 8. Look for one built a bit more recently with a parallel valve engine and composite or wood 2-blade prop and the weight should be under 1100. With the -1 wing, that gives you 400 lb for crew and 100 lb fuel. That should still give you 30-45 min of acro, 15 minutes to get back home and a 30 minute reserve. My Hangar neighbor competes in acro in a -4 and he never practices longer than 30 min at a time.

The difference between the 2 wings is the spars. The -1 spar is the same as is used in the 7/7A. Never asked Vans, but I'm sure it was to reduce tooling costs as much as anything. Max gross is the same (gear limited I think).
Yes, it seems heavy. There is not a lot of RV8's to choose from here in Europe, and most are too expensive.
Vans has told me that the reason for wing change is tooling cost.
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  #15  
Old 06-28-2018, 06:23 AM
Capt Capt is offline
 
Join Date: Feb 2017
Location: Australia
Posts: 211
Default

My 8 is just under 1200lbs m/t, well equip. I fly 99% solo so the weight isn't an issue for me but is probably one of the heaviest 8's I've seen. Great 1 up for aeros. I tried a 4 but way too limiting even for me solo. The 8 is the best design Vans ever made, well I reckon a pussycat to drive and idiot proof handling even on the ground
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  #16  
Old 06-28-2018, 09:17 AM
F1R F1R is offline
 
Join Date: Nov 2010
Location: ____
Posts: 612
Default Depends on your

Quote:
Originally Posted by HansR View Post
Hi.
I have yet not decided whether to buy a second hand RV8 or RV4.

My main target is to have an aircraft able to do aerobatics with two fullgrown males onboard.

On spec, everything points towards RV8, but when I found a plane of interest, it was with the Mark1 wing, with max aerobatic weight 1500 lbs.
The empty weight is 1140 lbs, leaving just 360 lbs for useful load. Even with the new wing with 1600 lbs aero weight, it is just 460 lbs useful weight. Not much fuel if the crew is 400 lbs.

I checked the RV4. It seems to be 1375 lbs max aerobatic weight, and 930 lbs empty weight, giving a 445 lbs useful load.

As far as I can see, the two planes have about the same useful load, providing a low margin for fuel.

How do you do with your RV4/8? Do you fly aerobatics with passenger?

Does anyone know the design difference between new and old wing?

Do you exceed the max aerob. weight if you stay below 4G?

What other advantages do I get with a RV8 (except a bit more room in the cockpit and more baggage)?

I really want an aerobatic RV, and I would like it to be aerobatic also with passanger. Please help me with the arguments for the two models.

My main target is to have an aircraft able to do aerobatics with two fullgrown males onboard.

Can't be done in a 4. And depending on your definition of two fully grown males, AND your definition of aerobatics, not even a great idea in an 8. Unless all you are going to do is aileron rolls.

An Extra 300 or SU 29 might be the safe solution depending on what aerobatics and how fully grown you and your passenger are.
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  #17  
Old 06-28-2018, 09:28 AM
RV8JD's Avatar
RV8JD RV8JD is offline
 
Join Date: Jan 2005
Posts: 884
Default

Quote:
Originally Posted by HansR View Post
According to Mitchell Lock, president of Vans, the max aerobatic weight with the old wing is 1500lbs.
Sorry, but the Aerobatic Gross Weight for RV-8s with the earlier “non-Dash One” wing is 1550 pounds.

See these documents from Van’s website as references:

http://vansaircraft.com/pdf/RV8wb.pdf

http://vansaircraft.com/pdf/RV8Awb.pdf
__________________
Carl N.
Arlington, WA (KAWO)
RV-8, 405 Tach Hours
(Pic 1),(Pic 2)
- Out with the Old, In with the New
(Pic)
RV-8, 1938 Tach Hours (Pic 1),(Pic 2) - Sold

Glasflügel Standard Libelle 201B, N564NS - Sold
Rolladen-Schneider LS1-f, N61MP - No longer owned

Last edited by RV8JD : 06-28-2018 at 12:32 PM.
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  #18  
Old 06-29-2018, 06:34 PM
Robert Anglin Robert Anglin is offline
 
Join Date: Mar 2008
Location: houston, texas
Posts: 868
Default Folow-up.

I don't know how to transfer to this sight. This question got me to thinking I should go back and look at my POHB to see why we built our C.G and weight the way we did. Keeping in mind that the 8 is a sport aerobatic, not a hard core aero platform, this may help if I can get it on here. We had to put samples of W&B in our POHB, so I pulled the one that gave the best look at a two person aerobatic configuration from it. Lets see if I can place it in here by long hand.
PILOT,PX, NO BAGS--------------WEIGHT-------ARM----------MOMENT
EMPTY AIRCRAFT-------------------1008------------------------79,527.18
FWD BAGGAGE---------------------------0----------58.51-------------0
FUEL ( 31.5 GAL)---------------------192----------80.0--------15,360.0
PILOT-----------------------------------190----------91.78------17,438.2
PASSENGER----------------------------185----------119.12-----23,037.27
AFT BAGGAGE-----------------------------0----------138.00-----------0
AFT BAGGAGE SHELF----------------------0----------152.91----------0
----------------TOTAL-----------------1575.0-------------------134,362.58
I think you can see that you can have some fun, even if it is not hard hammering. The rear C.G. moves up an inch from 86.82" to 85.82" and the weight is limited to 1600 Lbs. or 1550 Lbs. with the older wings.
I hope this goes and helps a little. Yours, R.E.A. III # 80888

sorry guys, I had this all spread out on each line, but it will not take it that way. I went back and added the dashes. I guess that matches our wing as well.

Last edited by Robert Anglin : 06-30-2018 at 06:41 AM.
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  #19  
Old 07-01-2018, 06:31 AM
HansR HansR is offline
 
Join Date: Jun 2018
Location: Sweden
Posts: 16
Default

Quote:
Originally Posted by RV8JD View Post
Sorry, but the Aerobatic Gross Weight for RV-8s with the earlier “non-Dash One” wing is 1550 pounds.

See these documents from Van’s website as references:

http://vansaircraft.com/pdf/RV8wb.pdf

http://vansaircraft.com/pdf/RV8Awb.pdf
OK, then Mitchell Lock at Van's is wrong, would be good, but I will try to get that confirmed.
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  #20  
Old 07-01-2018, 06:33 AM
HansR HansR is offline
 
Join Date: Jun 2018
Location: Sweden
Posts: 16
Default

Desicion taken, I bought the RV8.
Maybe I will replace the wing
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