What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

REALLY, REALLY long flight

F

fredmoss

Member
It's been a long time since I've posted (or even read the forum) because I've been stuck here in Singapore for two years and my building is put on hold.

However, the bug is still there and I do flight planning every single day (and studying for my IFR). I really want to take my RV (if it's ever finished) around the world to show her off.

One thing has been bothering me. And I'd like some input.

Many RV's have made the really, really long hop from Hilo, HI to Santa Barbara, CA (+2000NM) which equates to roughly 15 hours of flying time at 55% power. Now.. here comes the sticky part.

The useful weight of an RV-7 or RV-9 is under 600 lbs (even less kitted out for a global flight). If a pilot weighs in a 165 lbs and he has 30 lbs of kit (clothes, survival gear, a sandwich) that leaves only 435 lbs for fuel and oil before approaching Gross Weight.

Now, that equates to just over 60 gallons of fuel (45 in the wings and a ferry tank in the PAX seat) and with a burn rate of 6.5 GPH at 55% that give you just under 10 hours of flying (no reserve) -- a rough cruise speed of 150 knots at that speed give you a range of 1420NM OR about 600NM of swimming.

Jon Johansson did this in the RV4 by taking on a LOT of extra fuel with a ferry tank in his rear seat and wing tip tanks. But even a cursory look at the RV4 specs gives me approximately the same mathmatical problem.

So --- here it comes -- how do they do this? Are my performance figures 30% off -- OR -- are these long flights done significantly over Gross Weight.

I still have my lessons in my head about flying within the operating envelope and I'm still new enough to do a W&B everytime I take up a rental (even if I'm solo). I read about pilots going over GW all the time (as long as it's balanced) without problems.

Can anyone give me insight to this thorny issue?

Thanks!
 
fredmoss said:
The useful weight of an RV-7 or RV-9 is under 600 lbs (even less kitted out for a global flight).
Click to expand...
Typical empty weight of an RV-7 is around 1100 lbs. An RV-7 with Van's stock 1800 lb max gross = 700 lb useful load.

I don't know about this 45 gal in the wings thing. The RV-7 holds 42 gal (252 lbs) in the stock wing tanks.

Regardless, I think anybody serious about long distance ferry flights would need to make exceptions gross weight wise.
 
fredmoss said:
Jon Johansson did this in the RV4 by taking on a LOT of extra fuel with a ferry tank in his rear seat and wing tip tanks. But even a cursory look at the RV4 specs gives me approximately the same mathmatical problem.

So --- here it comes -- how do they do this? Are my performance figures 30% off -- OR -- are these long flights done significantly over Gross Weight.
Click to expand...

Jon Johansson did his takeoffs at several hundred pounds over the normally recommended gross weight.
 
Can't be done

fredmoss;156931 I still have my lessons in my head about flying within the operating envelope and I'm still new enough to do a W&B everytime I take up a rental (even if I'm solo). I read about pilots going over GW all the time (as long as it's balanced) without problems. Can anyone give me insight to this thorny issue? Thanks![/QUOTE said:
Mornin',
Short answer is that it can't be done within published weights. Did you notice how long Steve Fossett took to get airborne and the huge bow in the wings from all the load for his round-the-world flight? It can get really dicey since you're essentially on your own. Jon Johannson added weight in the rear incrementally and took off and landed with that weight aboard, exploring the handling and capabilities of his airplane heavily loaded.

Recently an across-the Atlantic trip ended in disaster shortly after takeoff in A modified Wheeler Express that was nearly double the manufacturers suggested max weight recommendation.

Not only would you need enough fuel for the trip but a safe reserve is a must. Jon's book detailing his trips is a good read and helpful resource if you're serious about doing this.

Regards,
Click to expand...
 
One, you will have to figure out where you could store some additional fuel in your plane, i.e. fuel bladder in the baggage area, wing tip tanks, etc and then apply to the FAA for a permit to fly your plane over gross, which is a temporary permit.

I flew my B55 Baron to Europe and back and had an aux fuel tank in the back seat area. When I would take off with full fuel I would be at 750 lbs over gross weight. Most planes will fly over gross, you just don't want to get into a situation in that configuration if possible. On the Baron, I had IO550's, I really couldn't even tell the difference in handling.

You would need to check with Van's and see what would be the max special gross weight that they believe you could have. I would think you could add an additional 60 gallons of gas, 360lbs, and still be ok, however I don't know your plane. I have an RV10.

Wayne Edgerton

RV10 N602WT
in the paint shop hoping to make LOE
 
Don't know if you noticed but there is a comment on Van's webpage about the MTOW of Jon's RV-4:

After reviewing Jon?s modifications and qualifications, Van felt comfortable issuing a one time approval for a take-off weight equaling 136% of the recommended gross.

Taken from this page: https://www.vansaircraft.com/public/jj-plane.htm
 
Maybe Steve Reynolds will chime in

As her is planning on flying his 7 from Euegene Oregon to Australia...

I believe his outboard wing section will be made to carry fuel...I.e the whole leading edge of the wing will be fuel.

This would be the most sensible place to put fuel as it would not add to the bending moment at the wing roots as it would if you put all the extra fuel in the fuselage.

I don't know the specifics but I could hook you up with Steve if he doesn't reply

Frank
 
frankh said:
As her is planning on flying his 7 from Euegene Oregon to Australia...

I believe his outboard wing section will be made to carry fuel...I.e the whole leading edge of the wing will be fuel.

This would be the most sensible place to put fuel as it would not add to the bending moment at the wing roots as it would if you put all the extra fuel in the fuselage...
Click to expand...
I took this picture at LOE 2002. The owners name is Jeff Nielsen. The tanks hold 120 gallons.

120.jpg
 
justinmg said:
I have an RV9. Can a 7 really do 150Kt at 55% power at MAUW?
Click to expand...
Yep, easily. My fuel burn at 150 KTAS is around 5.5 gph. FWIW, my normal travel (full throttle, 2280 RPM, 50 LOP) fuel burn is 7.0 gph at 165 KTAS.
 
Thanks!

Thanks for all the input -- I appreciate it. As it stands, my plane is just a emmpenage kit half built in my garage back in Australia. But, the reason I bought the plane is to fly it around the world.

Just to make things MORE complex. I was wondering where would be the best place to put the extra fuel. My thought was to -- for the duration of the global flight -- remove the right seat and replace it with a fixed fuel cell connected to the fuel tank gang switch on the center console.

Replacing a husky passenger (250lbs) with fuel shouldn't, theoretically, affect the handling characteristics -- as long as you are mindful of trim as you are using fuel from that tank -- right?

In addition, I believe there are wing tank extenders from SafeAir that increase your fuel load by another 9 gallons.

I understand that Van is the final arbiter of what can, and cannot, be done and I will ultimately ask this question of the company before building much more. But, I want to get as clear as picture of possible of what CAN/SHOULD be done before I do.

Of course, you CAN get across the Pacific on the northern route through Russia / Alaska but I'm lead to believe that AVGAS is difficult to come by in the Russian hinterlands and that could really create a problem.
 
How to make long flights?

In the immortal words of the guy I learned to fly jets from:

"They fly better over-gross, than they do out of gas"

TC
 
More gas

fredmoss said:
Replacing a husky passenger (250lbs) with fuel shouldn't, theoretically, affect the handling characteristics -- as long as you are mindful of trim as you are using fuel from that tank -- right?

In addition, I believe there are wing tank extenders from SafeAir that increase your fuel load by another 9 gallons.

I understand that Van is the final arbiter of what can, and cannot, be done and I will ultimately ask this question of the company before building much more. But, I want to get as clear as picture of possible of what CAN/SHOULD be done before I do.

Of course, you CAN get across the Pacific on the northern route through Russia / Alaska but I'm lead to believe that AVGAS is difficult to come by in the Russian hinterlands and that could really create a problem.
Click to expand...

I was thinking more than the little sareair extender tanks...More like build another tank where the fixed ribs are.. like an extra 20 gallons on each wing.

AVgas hard to come by?...What about 92 octane unleaded gas?...As long as your not running a lyc or clone over 8.5:1 CR it will be just fine. I been running it for 50 hours and with a max advance of 34 deg on the electronic ignition it runs exactly the same as on AVGAS.

Frank 7a
 
Another Can of Worms

Yea -- I saw the website for that Candian bloke (C-FSTB "Endurance") with 42 USG in each wing and that would just about do it. I'm sending him an email to see if I can get more details about his experience with W&B.

Also, this is an RV-9A using an engine conversion and (not wanting to start a flame war) but I'm wondering if an RV-9A with a IO-320 clone would be more fuel efficient in the cruise than an RV-7A with an IO-360 clone? Thoughts?

The other guy you mentioned (G-GDVR) did what I was thinking with an RV-6 -- a fuel cell in place of a PAX (much more useful) and wing tip tanks. I'm curious if there are any opinions here (silly question) of which would be superior. At least I know the RV-6 is proven.

That opens another question -- Ultimately, I think the best engine for any plane being built today would be a good diesel (or turbine) using Jet-A. You can get it anywhere and the quality control is typically better. You burn less of it per hour than you would AVGAS and it's cheaper. Also, I'm not worried about it being around in 15 years. However, I'm not keen on any of the diesel engines around (either too expensive or too unproven).

An engine that burns high-octane, unleaded MOGAS AND AVGAS would be second. For simplicity sake and ease of maintenance, I'm opting for a Lycoming clone (Superior XP) which, I understand, is approved for 91 Octane UL MOGAS. But, again, who knows if you can trust the same gas the guys at the Kamchatka aerodrome stick into their broken down Lada. Who wants to take off across the Bering Straight with dodgy petrol in your tanks? (Gee, I wonder if my survival suit is still under warranty?)
 
55 gallon drums

If you are in a "dodgy" place, usually you will have to purchase fuel by buying an entire 55 gallon drum of avgas. You'll want to make sure they open up a sealed container. :)
 
fredmoss said:
Also, this is an RV-9A using an engine conversion and (not wanting to start a flame war) but I'm wondering if an RV-9A with a IO-320 clone would be more fuel efficient in the cruise than an RV-7A with an IO-360 clone? Thoughts?

That opens another question -- Ultimately, I think the best engine for any plane being built today would be a good diesel (or turbine) using Jet-A. You can get it anywhere and the quality control is typically better. You burn less of it per hour than you would AVGAS and it's cheaper. Also, I'm not worried about it being around in 15 years. However, I'm not keen on any of the diesel engines around (either too expensive or too unproven).

An engine that burns high-octane, unleaded MOGAS AND AVGAS would be second. For simplicity sake and ease of maintenance, I'm opting for a Lycoming clone (Superior XP) which, I understand, is approved for 91 Octane UL MOGAS. But, again, who knows if you can trust the same gas the guys at the Kamchatka aerodrome stick into their broken down Lada. Who wants to take off across the Bering Straight with dodgy petrol in your tanks? (Gee, I wonder if my survival suit is still under warranty?)
Click to expand...



Well you have a ways to go before your selecting an engine but if it were me I'd want the most proven thing out there...and that would be a Lyclone, running a mag and a Ligtspeed...Simply from the proven record of this setup.

And i run An e/Pmag combo...Its just that for your trip I would want PROVEN reliability....Note I also get scared over the edge of Lake Tahoe!

As to the O320/360 question...I doubt it would make much difference (I'm assuming a C/S prop here from an efficiency standpoint)...But note that the IO540 drivers see less fuel burn when running lean of Peak than the 4 bangers do...Maybe running a motor at 30% power is more efficient than running at 55%?..Who knows, but bottom line the 360 maybe slightly more fuel efficient than the 320.

Don't get too wrapped up in what suppliers "approve" for fuel. They are either ECI or Superior component engines. At 8.5:1 CR they all run equally well on 91 mogas.

Note a number of RV9's have 360 cubic inch motors on them. The 9 wing is i believe a little more efficient too?

A well balanced Fuel injection goes without saying...its worth at least a gallon per hour over a carbed motor that may not be able to be run LOP.

Good luck...I think your nuts..:)

Frank
 
Any chance of a new route through China to Siberia....and across the Bearing sea to Alaska???? It is only about 27?miles of water. Not sure if the political environment would allow this???
 
Hmmmm

TerryWighs said:
Any chance of a new route through China to Siberia....and across the Bearing sea to Alaska???? It is only about 27?miles of water. Not sure if the political environment would allow this???
Click to expand...

Let me see, its s toss up between being shot down or drowning...:D
 
You might have trouble getting across the Bearing Sea. The weather up there is bad most of the time (some of the worst in the world). A lot of waiting time on the ground for the right wx.
 
Actually -- there is an approved VFR route from Provideniya Bay to Nome, AK and here is the link.

http://www.alaska.faa.gov/Internat/Russia/Russia.cfm

However, to get to Provideniya Bay from Australia means either tracking through Japan or China / Sakhalin Islands / Kamchatka. I've actually flown in Japan before (expensive) and my friends who have flown through China say the ATC are incredibly sadistic to commericial and GA flights as well (on the spot regulations and arbitrary decisions).

I have also travelled in Russia (but not flown there) and I can tell you that telling a Russian that he MUST open a fresh drum of fuel or MUST comply with a published procedure is the conversational equivalent bashing your head against a brick wall. Not even tossing about liberal quantities of $$$ will help if his mind is made up. Not a good place to be stranded. All up, I would prefer the South Pacific / Christmas Is / Hawaii / West Coast route.

I'm intriqued by the idea that an IO-360 can get more NMs out of a gallon of fuel than an IO-320. Does anyone out there have any burn rate / mileage figures from their own flying ships? I had already made the decision to use fuel injection. What about the Lightspeed Mags -- do they really offer up measurable fuel efficiency?
 
Solution: Aircraft carrier !!

Doesn?t anybody have a friend in the high ranks of the Navy? Maybe he could persuade his friend to allow you to drop by on his Aircraft carrier, for refueling and the use of the toilets, while he is circling somewhere in the middle of your ocean crossing trip. :cool:

How about, if you new where they all are (the aircraft carriers) and you just declare an emergency, when you are near to one of them, would they refuel you and let you take off to finish your journey? :rolleyes: It's a shame Google-earth is not "live".

What about a group-buy of a redundant aircraft carrier? :D So we can have trips around the world when ever we want, as long as the group is big enough. How much does a second hand aircraft carrier cost? :confused: Questions, questions??
 
Wrong Fuel

Interesting idea -- but the problem is US Navy ships don't carry any AVGAS. There is no need, all their aircraft use JET A (I believe they call it JP5). So, no refueling. There are only two reasons to land -- one is for fuel and the other for food.

Also, those cables on the flight deck play havoc with your nose gear. I flew into a US Airbase in Japan that had dummy arrestor cables installed on the runway for training purposes. They nearly tore the nose wheel off my C-152 (OUCH!).

I wouldn't want to roll over them with a RV-7A (given the history of nose-wheel incidents).
 
You must log in or register to reply here.
Back
Top