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-   -   RV-7A - Weight & Balance concerns. Is it the right plane for us? (https://vansairforce.net/community/showthread.php?t=128603)

BruceEicher 08-15-2015 03:08 PM

Quote:

Originally Posted by Oliver (Post 1006230)
Admittedly, I am new to experimentals, so please excuse my ignorance. I thought that during Phase I testing, the entire flight envelope, including the stall speed at different bank angles, will be tested and the POH created based on these results!?
o

I would say that an average guy's 25 to 40 hours of Phase One "test" flying does not erase or override the designer's recommendations. IMHO...YMMV...

Oliver 08-15-2015 04:02 PM

I am getting really unsettled, as I have received a number of messages, e-mails and responses in this thread, suggesting that I should never exceed the 1800 lbs, Van's mentions on their website.... :(
I don't see the danger in such a small increase of the gross weight, 1850 lbs would probably already suffice, but then again I want us to be safe and don't do anything stupid.

I also had a closer look at the RV-14. This certainly seems to be a nice plane, but another $20 - $30k, only to be able to haul maybe 60 lbs of camping gear or heavier baggage every once in a while, with which we would exceed the RV-7's gross weight by around 35 lb!? :confused:

I guess we'll have to seriously reconsider our options: RV-7A project, RV-14A QB-kit or to simply get a Cessna 182, what we were initially planning for. My wife isn't too excited about a retract, a v-tail Bonanza might however also be an option.

BillL 08-15-2015 04:27 PM

Quote:

Originally Posted by Oliver (Post 1006271)
I am getting really unsettled, as I have received a number of messages, e-mails and responses in this thread, suggesting that I should never exceed the 1800 lbs, Van's mentions on their website.... :(
I don't see the danger in such a small increase of the gross weight, 1850 lbs would probably already suffice, but then again I want us to be safe and don't do anything stupid.

I also had a closer look at the RV-14. This certainly seems to be a nice plane, but another $20 - $30k, only to be able to haul maybe 60 lbs of camping gear or heavier baggage every once in a while, with which we would exceed the RV-7's gross weight by around 35 lb!? :confused:

I guess we'll have to seriously reconsider our options: RV-7A project, RV-14A QB-kit or to simply get a Cessna 182, what we were initially planning for. My wife isn't too excited about a retract, a v-tail Bonanza might however also be an option.

It is not just the money, the newer kit will go much faster. Here is the post I remembered, it has a phone number. I might be the answer to all of your wants. http://www.vansairforce.com/communit...d.php?t=127724 A discussion with Tom can not hurt.

Ironflight 08-15-2015 04:31 PM

Oliver, the problem with the approach of "I'll test it in Phase 1, and then I'll always remember to fly it in those limits" is that you are relying on the pilot never making a mistake later on. In the risk management business, we call that relying on an Operational Control of risk - and while that might be a good approach if there is one additional backup to a pilot mistake, it certainly puts you way out there on the risk meter if a single (simple) failure can be fatal. Heavy AND aft CG is a good recipe for pilot overcontrol.

I agree with you that you might want to look at other options, no matter where that search leads - even away from RV's. Pick the airplane that fits your requirements.

BobTurner 08-15-2015 04:46 PM

Oliver,

Take a deep breath, relax. With this kind of money at stake, you need to take your time, think thru and check out all options (even non-RV!).
Have you and yours sat in a -7? in the -14? There is no question the -14 is more comfortable, but only you or, especially, your wife, can say how much more or if the -7 is too cramped to be tolerable.
As a long time 182 owner I will say it is a great airplane, and maybe that is what you want. Compared to an RV it is slow, and burns a lot of gas. But if you only take short trips that won't matter. Of course it won't do aerobatics.
Building is not for everyone, and if that's not you, that's okay. It does rule out the -14 in the near term as none are built and for sale yet.

jrs14855 08-15-2015 04:59 PM

Landing Weight
 
Quote:

Originally Posted by Ironflight (Post 1006220)
Remember though - staying safer is a matter of building margin. So let's say to have just taken off at your 1900 lb weight, and smell smoke in eh cockpit. You decide that you really REALLY want to be on the ground right away, and pull it into a tight pattern. Tight enough that forget that the stall speed in a steep turn is also dependent on weight - stall/spin on the final turn.

Airplanes that have a lower landing weight than TO weight generally have a fuel dump capability. Thats to provide operational margin. Aircraft design limitations should not be defined by desire to "That looks about right".

Will it work? Sure - if everything goes right. But what if it doesn't? Everyone is free to decide for themselves of course - but everyone should evaluate the risk/trade for themselves as well. SOmeone will search this thread in the future for justification extend their Gross to 1950....

For two large people that want a two-seater to carry luggage and fuel cross-country? That's what the RV-14 is for.

I have to disagree with the statement about fuel dump. I have flown most of the popular light twins and turboprops. I don't remember a single one that has fuel dump. Some approve landing at max takeoff weight, many do not. A company that I worked for, long before I worked there, allegedly operated with total disregard for landing weight. They did a lot of very short positioning flights where the landings were well in excess of the maximum approved landing weight.
On one fairly rare model of the DC9, the airplane was certified without a fuel dump system. Landing weight was 102,000 and takeoff 114,000. A return after takeoff with overweight landing required a fairly simple overweight landing inspection.

jrs14855 08-15-2015 05:06 PM

Phase One
 
Quote:

Originally Posted by Oliver (Post 1006230)
Admittedly, I am new to experimentals, so please excuse my ignorance. I thought that during Phase I testing, the entire flight envelope, including the stall speed at different bank angles, will be tested and the POH created based on these results!?
Now, 'forgetting' is a different story, which is IMHO however not directly linked to an increased gross weight... ;)

The RV-14 would indeed be a nice two person travelling machine and might indeed be an option if we are able to find a project, as I am concerned that I might not have the patience to work on a kit for around 3 years. :o

The new format for ops limitations require only Vso, Vx, Vy and the weight and cg where these numbers were obtained. There is a paragraph about "throughout the normal operating speed range" or words to that effect, which would IMPLY testing to Vne, among other things.

jrs14855 08-15-2015 05:19 PM

Gross Weight
 
If you look at the history of most US light aircraft that had a long production run, in most cases you will find significant gross weight increases over the years. In many cases there were no structural changes for the weight increases.
A few examples:
Piper Aztec 4800 to 5200 gross
Piper Commanche 2800 original 250 to 3100 for 260
Bonanzas had a gross weight increase nearly every model, sometimes there were structural changes sometimes not.
DC3's in WWII were routinely flown 30% above the original civilian weight.

wirejock 08-15-2015 05:57 PM

Baggage
 
My 7a is not finished but I'm trying to keep her light. I carry around enough already.:eek:
Sweetie and I used to travel a lot on our Goldwing. Pretty limited on baggage so we learned.
A few times we shipped stuff to the destination and shipped stuff back.
So basically we will learn to live within the limits of our airplane.
Just a suggestion.

Mel 08-15-2015 06:06 PM

Quote:

Originally Posted by jrs14855 (Post 1006289)
The new format for ops limitations require only Vso, Vx, Vy and the weight and cg where these numbers were obtained. There is a paragraph about "throughout the normal operating speed range" or words to that effect, which would IMPLY testing to Vne, among other things.

Gonna have to jump in here. You must test the aircraft "throughout the aircraft's normal range of speeds and throughout all maneuvers to be executed."

Vso, Vx, Vy, and the weight and CG location at which they were obtained are the only numbers required to be listed. That does NOT mean that these are the only numbers that require testing.


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