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Maximum Gross Weight for a RV6

Hugues

I'm New Here
I bought my RV6 2 years ago , I bought a new engine (1-360) with a CS prop and I realized that the gross weight specifed in the journey logbook is 1,780 pounds...

On the Van's website it's written 1,600 pounds :rolleyes:

Does someone can help me to clarify the situation ?
 
The builder at time of completion can specify any weight they choose. Hopefully it was properly tested during phase 1 at the increased weight. The new number changes the max weight legally but it can?t change physics.

That?s how it works in the US. Not sure if there are any differences up north.
 
The kit manufacturer says 1600lb.
Lots of people who have shown no engineering to back it up say 1800lbs.

I know where i'd place my bets.
 
The kit manufacturer says 1600lb.
Lots of people who have shown no engineering to back it up say 1800lbs.

I know where i'd place my bets.

I don't disagree with this position. However, when Vans added 45 some odd pounds with the introduction of the A model, they upped the A model's gross to 1650, eventhough no modifications were made to support more weight, just the need to maintain the same usable load (one could potentially argue that the A model's gear is slightly stronger due to it' mounting method, but everything else is the same) Clearly there must be some decent margin there. That said, Van's in their designed load must account for builder variability and significant construction quality variances, especially in the earlier models without pre-punched panels and builder constructed spars. I suspect that greater construction quality varibability equates to greater safety margins; At least for the more conservative companies. IMO, the 7 kit would result is less variability and therefore the ability for more traditional margins. Just a hunch.

Larry
 
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I don't disagree with this position. However, when Vans added 45 some odd pounds with the introduction of the A model, they upped the A model's gross to 1650, eventhough no modifications were made to support more weight, just the need to maintain the same usable load (one could argue that the A model's gear is slightly stronger due to it' mounting method, but everything else is the same) Clearly there must be some decent margin there. That said, Van's in their designed load must account for builder variability and significant construction quality variances, especially in the earlier models without pre-punched panels and builder constructed spars.
You're right, I glossed over that as the question was specifically about the RV-6.
I could accept without engineering data that the -6 could fly at 1650 lb without issue, as long as you didn't land it (or landed it very carefully) over 1600 lb.
 
Clearly there must be some decent margin there. That said, Van's in their designed load must account for builder variability and significant construction quality variances, especially in the earlier models without pre-punched panels and builder constructed spars.
Larry

Do you what that "decent" margin is? Do you know how much of that margin you have used up with the variability in you build?
 
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Do you what that "decent" margin is? Do you know how much of that margin you have used up with the variability in you build?

I have no idea. It is speculation on my behalf. I just shared the rationale for that speculation. I would find it surprising if a respectable and conservative company like Vans didn't build in extra safety margin to account for build quality variance. The question then is how much. The bigger question is where any given plane sits on that variance scale; mine included. I think that I did a good job and most key stuff was done in the factoy (QB), but who knows.

This was just off the cuff thoughts and not a recommendation to increase gross weight.

Larry
 
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Legally, the Max Permissable Take-off Weight listed on your CofA is your max gross weight for your aircraft. What is listed in the Journey Log should be the same number.
Being higher than Vans recommended gross weight should be a concern to you (or not) only as it affects structural and flight limitations. Be sure you understand how this affects how the plane flies, how loading or modified loading limits should be observed, including what your G Loading and CofG range should be (would be wise to move your personal Aft CofG limit forward a bit). As you bought the plane with this number attached to it, you didn't have the advantage of the builders justification for increasing the Max Gross over the kit manufacture's tested value. It's up to you to fly it to your personal limit... of course not over what's listed on your CofA.

You mention the new engine & prop. Are these upgrades? if so, these affect your CofA and TC should be notified. You could also talk over the 1780 gross and get their take on effects on structural loading and effects to operation. They are good folks to talk to.
 
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This was just off the cuff thoughts and not a recommendation to increase gross weight.

Larry

Thank you for the response I was hoping for. We are arguing the same point. I was just approaching it differently. I would not recommend randomly increase gross weight, Vne, or anything else unless people know more or test more.
 
However, when Vans added 45 some odd pounds with the introduction of the A model, they upped the A model's gross to 1650, eventhough no modifications were made to support more weight, just the need to maintain the same usable load (one could potentially argue that the A model's gear is slightly stronger due to it' mounting method, but everything else is the same)

A little research shows that this is not correct.

Here is published specifications for the RV-6 from 1997 dredged up using the wayback machine.....

http://web.archive.org/web/19970628181508/http://www.vansaircraft.com/models/rv6.htm

Here is the same for the RV-6A......

http://web.archive.org/web/19970628181514/http://www.vansaircraft.com/models/rv6a.htm

It shows that the delta between the official published empty weights of the RV-6 and RV-6A was 20 lbs.
This is pretty close to what the weight difference has been on customer built airplanes over the years if all other things were equal (Engine, Prop., avionics, etc.).
 
If it was built in Canada it will only be approved at Van's numbers,no increases allowed. If it was built in USA and imported the MOT will allow the gross weight specified on the data plate and log book
 
Yes, that?s MDRA requirement.
After you receive your final CofA, you can request direct to Transport Canada for changes, such as engine or prop change, IFR approval, aerobatic maneuver operating limitation, or gross weight increase. In some of these you surrender your existing CofA, apply for Temp Flight Permit to test whatever change, submit test reports & they issue a new CofA with new operating limitations.
 
Maximum Gross Weight RV6

Thank you for all your comments
My new 0-360 is the same type of engine it had
I talked to the guy he flew it for 900 hours and he did not have any problem at 1,750 pounds ,even at high altitude in different configuration...

Of course , it is not the time to fly aerobatic manoeuvers
The aircraft has been built in Canada and I will check with Transport Canada if their documents confirm the 1,750 pound MGW and how the TC inspector approved this increase of the MGW
 
You shouldn't have to check with TC. Your gross weight should be listed on your CofA/CofR documents tucked into your journey log. I'm pretty sure you'll find its Van's original specs for that model.
 
I bought a 2002 RV6A built in Canada, and have all the original documentation for the CofA with gross weight tested to 1800lbs, not Vans' 1650.
 
I grossed my 6 to 1650 as that is what worked for me, tiny wife, full fuel, and 100# of bags. (doesn't matter if we are gone for two days or a week, she will have 100# of bags). So, I am "legal" to take off.
I can tell you that landing at near the 1650 gross, I would never consider 1750, let alone 1800. I don't like how the airplane feels.
Whether it can take it or not is speculation. I have had enough hard landings at nowhere near gross to convince me.....I don't want to fly heavier. I don't even want to fly at 1600 if I can help it.
 
Dale - sometime after 2002 MDRA decided they would only process CofA applications with Max Permissable Weight at the Kit Mfgr suggested max published value. They would not accept anything higher even if the value was calculated per Transport Canada?s published formula.

JonJay - the feel gets more interesting as fuel is burnt off & CG shifts back.
 
My experience with RVs is a grand total of 1 RV7A, and my 6A.

I'm not sure what you mean by the feel changes...I fly it and land it quite well. It doesn't get a heavy, or squirrelly feel as fuel burns. I have flown it solo with light fuel, and full fuel with two 200 pounders in the seats, and I can honestly say there is no noticeable negative feeling in the airplane.
 
My experience with RVs is a grand total of 1 RV7A, and my 6A.

I'm not sure what you mean by the feel changes...I fly it and land it quite well. It doesn't get a heavy, or squirrelly feel as fuel burns. I have flown it solo with light fuel, and full fuel with two 200 pounders in the seats, and I can honestly say there is no noticeable negative feeling in the airplane.

If the baggage area was empty in the above example, for most RV-6's or 7's you would still be well fwd of the aft C.G. limit.

With 100 lbs in the baggage compartment and a lot of the fuel burned off, the C.G. is often near the aft limit. In that case the feel is definitely different. Particularly in the landing flare.
 
If the baggage area was empty in the above example, for most RV-6's or 7's you would still be well fwd of the aft C.G. limit.

With 100 lbs in the baggage compartment and a lot of the fuel burned off, the C.G. is often near the aft limit. In that case the feel is definitely different. Particularly in the landing flare.

Absolutely correct.

During my phase one, one of the things I investigated was stick force per G, and it does get significantly lower as the CG moves aft. Note that this was at quite a bit less than MGTOW. Higher load factors approached zero stick force per G at rearward CG points and I suspect a reversal is very possible at even minute amounts aft of the rear limit.
 
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If the baggage area was empty in the above example, for most RV-6's or 7's you would still be well fwd of the aft C.G. limit.

With 100 lbs in the baggage compartment and a lot of the fuel burned off, the C.G. is often near the aft limit. In that case the feel is definitely different. Particularly in the landing flare.

I can second that, though I can't get anywhere near 100 lbs in the baggage area with my FP prop. I have noticed no meaningfull difference landing light vs gross, though I definitely notice it just after rotation in the summer. Aft CG is is a whole nother animal. If I put the max amount of baggage in the back. regardless of total weight, it feels WAY different in the flare. Not unsafe, just requires you to realize it is coming and be very light in your stick control. The first time scared the @#$# out of me, as it felt like I was pushing on the stick to get the nose up in the flare. In reality, I think I was just pushing away from where my muscle memory took the stick, which is too much when CG is far aft.

Larry
 
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To help a bit when loaded down in the side by sides, I have created a tall bin I mount over the center tunnel, I load small heavy items like tool kits, blow up air mattresses, wife's bathroom kit, etc. and securely strap it in there. This helps some in distributing the CG forward.
 
To help a bit when loaded down in the side by sides, I have created a tall bin I mount over the center tunnel, I load small heavy items like tool kits, blow up air mattresses, wife's bathroom kit, etc. and securely strap it in there. This helps some in distributing the CG forward.
Yes, pillows and sleeping bags against the baggage bulkhead, and tiedown kit and tools under your thighs!
 
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