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-   -   RV-9 increased fuel capacity (https://vansairforce.net/community/showthread.php?t=97892)

PJ79 03-27-2013 04:05 AM

RV-9 increased fuel capacity
 
Hi All,
Ive been wanted to build an RV 9 for years and am going to bite the bullet this week before the price rise. The only concern I have is the fuel capacity on the 9. I know there are other threads addressing this issue but would love to hear from someone who has increased the standard tank size. Im hoping to do this by increasing the number of bays used.
Also any other advice for a newbie would be greatly appreciated.
Thanks in advance
Pete

Vlad 03-27-2013 04:31 AM

Pete welcome! I have standard fuel tanks but would love to have full leading edge tanks like these. It's a lot of extra work you have to fabricate your own leading edge skins.




XOverZero 03-27-2013 07:24 AM

Pete,

Again, welcome. A buddy in our EAA chapter installed aux tanks in his TD -9, filled from a second set of ports in the tips. My WAG is that his mod would likely be easier than a complete redesign of the standard tanks. He's not on this forum, so I'll ask him about the details and get back to you...may take a few days.

TThurston 03-27-2013 07:37 AM

RV-14
 
Wanting larger fuel tanks sounds like a reason to consider the RV-14.

Rupester 03-27-2013 08:17 AM

I echo TThurston's comment.

rv9av8tr 03-27-2013 08:25 AM

Quote:

Originally Posted by TThurston (Post 756535)
Wanting larger fuel tanks sounds like a reason to consider the RV-14.

True enough, but for those already commited to their existing project....

I built 2-8 gal tanks out of fiberglass using the Rutan Long-EZ tank technique. They fit behind the seat backs so the CG arm is near the pilot station. The tanks cross tie and feed directly into the Van's standard fuel valve port that is otherwise plugged. I have the design set up for single or duel tank installation.

My brother built an Al tank that fits on the baggage floor for his -9A, though he's not yet flying.
I've found that using just one of my tanks has been plenty fuel for a "typical" cross country. I take off and climb on the Aux tank when burn rate is highest to use it up soonest and burn it off to "dry". Then settle into the rest of the flight LOP at altitude. Typically gives me 6 hrs of flight time and around a 1,000 air miles.

https://plus.google.com/photos/11665...129?banner=pwa

pierre smith 03-27-2013 08:48 AM

Quote:

Originally Posted by PJ79 (Post 756484)
Hi All,
Ive been wanted to build an RV 9 for years and am going to bite the bullet this week before the price rise. The only concern I have is the fuel capacity on the 9. I know there are other threads addressing this issue but would love to hear from someone who has increased the standard tank size. Im hoping to do this by increasing the number of bays used.
Also any other advice for a newbie would be greatly appreciated.
Thanks in advance
Pete

Pete, there are the Safe-air tanks that give you another 10 gallons or so, if that's enough. They're filled at the wingtip, under a flip-up door you install and consist of an aluminum tube that slides into the holes in the ribs.

Here: http://www.safeair1.com/fueltanks/rv9ertanks.php

Best,

Tumper 03-27-2013 10:02 AM

Aux Tanks
 
Pete,

I have the Hotel Whisky Aux tanks on my 9. Now I haven?t flown yet but there is a guy out in West Texas that has. There are also plenty of RV-8 and RV-7 guys that have the Hotel Whisky tanks.

They are well built and fairly simple. I highly recommend them.

Mel 03-27-2013 10:26 AM

I've been flying with Hotel-Whiskey extended range tanks in my -6 for over 3 years and love them!

Basically these tanks are designed to give a little over 1 hour of extended range on each model.

RV7Ron 03-27-2013 10:42 AM

I did a smaller version of the "Tuckey Tanks"...about 9 gallons each side from my volume calculations, so I should be around 60 gallons total. Not flying yet so no PIREPS but plenty of people have done this mod, it wasnt very difficult and fairly inexpensive. It is more work though, no doubt.

http://ronsrv7project.blogspot.com/2...obbs-3380.html

Click on the link in my post for "Pat Tuckey" and he has a great detailed writeup on how to do it. Good luck!

PJ79 03-27-2013 11:23 AM

Hi Everyone,
Thanks for your replies. Yes I have looked at the Tip tanks and they may be the option I go for if it turns out much easier. I certainly would love to try the RV 14 but am concerned that the costs will end up blowing out due to the cost of the 390. From what I have read it can more than 10k more.
Does this sound right?
I have seen on a builders log (Bretts RV 9a) that you can buy kit engines to save on costs. I have a good friend who is an extremely talented fitter who may be interested in assembling the engine for me if i go that way. Has anyone else had experience with kit engines?
Once again, thankyou for all your replies and your warm welcome.
Look for to corresponding alot more as I get into the details and my kit arrives! :D

Av8torTom 03-27-2013 12:17 PM

Hummmmm
 
37 gallons at a conservative burn of 10 gallons/hour = 3 hrs in the air with reserves. About as long as I want to spend in the air before I want to stretch my legs... but that's just me. :D

airguy 03-27-2013 12:25 PM

Quote:

Originally Posted by Av8torTom (Post 756631)
37 gallons at a conservative burn of 10 gallons/hour = 3 hrs in the air with reserves. About as long as I want to spend in the air before I want to stretch my legs... but that's just me. :D

In general, for passenger comfort, you would be correct. However, some of us may want to make long over-water flights where the fuel would be needed. I know that was my reason for building the extended tanks in my 9A.

alpinelakespilot2000 03-27-2013 12:27 PM

Quote:

Originally Posted by Av8torTom (Post 756631)
37 gallons at a conservative burn of 10 gallons/hour = 3 hrs in the air with reserves. About as long as I want to spend in the air before I want to stretch my legs... but that's just me. :D

And that's if you're willing to burn 10gph. If you look through the threads you'll see that many -9 pilots tend to pull the power back for cross country cruise. 60-65% power can be done at about 6-7 gph and still yield 140-150 kts TAS. That means standard tanks really give you about 5-6 hours of economy cruise.

Thus, I'm in the camp that extra tanks are really not necessary for me but, if they were, I would definitely go the route of adding after-market tanks rather than structurally changing the wings, especially given all the complexity, time, expense, and engineering questions that go along with doing that.

PaulR 03-27-2013 12:31 PM

Endurance
 
I'm a little like Av8tor. I'm 57 and the fuel tanks in my 9A are a LOT bigger than my bladder!!!! ;) Plus, as comfy as Abby's seats are, I still want to stretch my legs at least by the 3 hour mark!!!!

PJ79 03-27-2013 12:53 PM

Hi all,
Thanks for all your replies. Im not trying to question anyones bladder. Just wanted the option of not having to fill up everytime I land as quality fuel might be an issue in some areas here. I was hoping to get specific details of how people have increased fuel capacity. Im leaning toward tip tanks at the moment but will make that decision when my plans arrive and I assess the wing design. I just thought anyone who had increased the number of bays used in the tanks might be able to give me details.
Thanks :)

pierre smith 03-27-2013 01:15 PM

PJ, the variations of extra tankage are plenty, from 50% more fuel to full length leading edges.

A lot of the guys who build Super -8's (IO-540's) and Super -7's, buy a single tank skin from Van's, cut it in half and add one section to each outboard end, adding 50% more, or thereabouts, because of the higher fuel consumption of the big engines.

Read about Jon Johannson on Van's front page. He's in Oz and had 18 hours aboard his -4 for his two round-the-world flights, including 50 gallons in the back seat!

Best,

Bevan 03-27-2013 01:48 PM

Quote:

Originally Posted by PaulR (Post 756644)
I'm a little like Av8tor. I'm 57 and the fuel tanks in my 9A are a LOT bigger than my bladder!!!! ;) Plus, as comfy as Abby's seats are, I still want to stretch my legs at least by the 3 hour mark!!!!

3 hours outbound and 3 hours back equals 6 hours plus reserves. I like to go places that doesn't have fuel (and people).

Bevan

MauiLvrs 03-27-2013 11:09 PM

Quote:

Originally Posted by Av8torTom (Post 756631)
37 gallons at a conservative burn of 10 gallons/hour = 3 hrs in the air with reserves.

At an economy cruise near 6gal/hr is 6 hours...
The best way to get a bit more gas if you are building the tanks is to extend the tanks out to the next rib...


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