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Cozy Mk IV range extension


afks05

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I'm trying to decide on the feasablility of really extending the range of a Mk IV, and need a sanity check from any willing.

 

I figure if I can create a (hopefully removable) fuel tank for the back seat of the Mk IV I can convert all the rear pax (and seats) weight into fuel (in the neighborhood of 450lbs). By my calculations that still keeps the CG in range. Then if you pick up a few gallons in the baggage compartment, and strakes, then you end up pushing the range of the Mark IV over 3000nm.

 

I figure with two pilots (both IFR, oxygen, and piddle pack qualified) we could endure the flight, and actually do private trans-atlantic kinda stuff.

 

Any thoughts?, gotchas? ect?

 

Thanks,

Kyle

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.....you end up pushing the range of the Mark IV over 3000nm.

 

I figure with two pilots (both IFR, oxygen, and piddle pack qualified) we could endure the flight, and actually do private trans-atlantic kinda stuff.

 

Any thoughts?, gotchas? ect?

 

Thanks,

Kyle

You can do transatlantic flight with the longest overwater leg only being 4-500 miles max. I cant for the life of me envision wanting to be in a small plane cockpit for 12-15 hours... but what you describe is do-able.

 

Talk to your doctor about DVT prophylaxis before taking any super long trips like that.

 

Dave

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I'm trying to decide on the feasablility of really extending the range of a Mk IV, and need a sanity check from any willing.

I seem to have become a resident expert in sanity checks.

 

I figure if I can create a (hopefully removable) fuel tank for the back seat of the Mk IV I can convert all the rear pax (and seats) weight into fuel (in the neighborhood of 450lbs). By my calculations that still keeps the CG in range. Then if you pick up a few gallons in the baggage compartment, and strakes, then you end up pushing the range of the Mark IV over 3000nm.

Physically what you propose is eminently possible. I considered (for about .003 seconds) doing the same thing to extend the range, until I actually SAT in my plane in the air for 4.3 hours and decided that 5 hours would probably be the point at which I'd start waving the UZI around and demanding that the pilot land the freaking plane. Cuba - Afghanistan - don't care - just get the thing on the ground.

 

There are a few issues, however. First: with the 1000 lb. payload of the MKIV and 320 lb. in the regular tanks, adding 450-500 lb. of fuel will take up ~800 lb of the 1000 lb. That leaves you room for ONE person, not two, unless you want to start the flight 200 lb. over gross (and get the permits to do so, or else certify the aircraft at a MUCH higher weight than anyone else has done).

 

Secondly, carrying ~800 lb. of fuel, or about 133 gallons, will get you somewhere between 2000 NM and 3200 NM range, depending upon speed and fuel flow (assuming no wind). Assuming that you want at LEAST IFR reserves, you've actually got about 125 gallons usable. At a fuel burn of 10 gal/hr (full throttle at 8K ft.), you'll true out at about 180 kts. That'll get you 2250 NM, or just about the distance from LA to Honolulu, in about 12.5 hours (no wind, remember). If you're willing to throttle back to 7-8 gal/hr., you'll get about 160 kts and maybe 2600 NM range. You'll be in the air for 18 hours. If you REALLY want to extend your range, and fly at best L/D speed (about 100 kts) with a fuel burn of ~4 gal/hr, you'll get the 3000 NM range, but you'll be in the air for close to 31 hours. Yeah, right.

 

As you postulate, any weight in the rear seats doesn't change the CG much, and building a tank and tapping into the fuel line is NOT anything insurmountable for someone that's built an airplane - it's been done before.

 

I figure with two pilots (both IFR, oxygen, and piddle pack qualified) we could endure the flight, and actually do private trans-atlantic kinda stuff.

As Dave S. points out (and the web page http://xpda.com/flyingtoeurope/ clearly shows) there's no need whatsoever for extended tanks if all you want to do is cross the north Atlantic. Even flying the South Atlantic, from S.A. to Africa, only requires about a 1500 NM range.

 

Cross Pacific flying is really the only place where you need the extended range.

 

So, it is possible, with a COZY? Sure. It's been done with L.E.'s, and it's only easier with an airplane that can carry twice as much payload.

 

Just remember that the last person to attempt it, in a COZY III from Hawaii to the mainland, crashed a couple hours out of Hawaii, lost his plane, and had to be rescued and was lucky to survive.

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I perform several cross countries every year (Coast to Coast). Generally, these are non stop when flying west to east, but I usually make one fuel stop when westbound. Eastbound trips are almost always done GPS Direct, at FL210 - FL230. Check Tail winds and pick the best altitude. File VFR Flight following with a cruise altitude of 17,5. After you achieve your cruising altitude and everything is stable, refile for FL210.

 

I won't fly in instrument conditions at these altitudes, Its to easy to pick up ice.

 

TIPS:

 

Auto Pilot is a must.

 

Good Cabin heat system. An exhaust heat muff won't cut it.

 

Relief tube system

 

Things to keep you occupied, I usually take magazines, news papers, etc. I'll be installing a DVD player in the instrument panel, so this should help on future trips.

 

 

I would not consider an ocean crossing in a single engine aircraft unless it was a very special occation i.e. one way, delivering a purchased aircraft. Generally, any mechanical problem will result in total loose of the aircraft, and place the pilot in grave danger.

 

In simple terms, To me, the return is not worth the investment.

 

ALSO: at $4.00 per gallon, round trip airfare is almost always cheaper than IFLYEZ airlines.

 

Waiter

F16 performance on a Piper Cub budget

LongEZ, 160hp, MT CS Prop, Downdraft cooling, Full retract

visit: www.iflyez.com

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Ok some follow ups:

 

Does anyone know the glide ratio of a Cozy Mk IV? Cause if you go engine out it would be nice to know how far you can glide.

 

Also you need pressure breathing above FL280 so you could push your altitude up just shy with just oxygen.

 

Second, has anyone tried taking off over gross weight? What is anyone's best guess of the runway needed for 500lbs overweight (infinite?)

 

As an aside I'm not sure flying the quazi over the top via greenland route is that much safer, Because basically if you lose your engine anywhere more that 100miles north of the US-Canadian border you're dead. Crash-land in the forest - your dead, bailout in northern canada - probably dead, ditch in the north sea-definately dead. Agree however that minimizing over water time = good.

 

Realize this all sounds rather nuts, I'm fine with that. I appreciate all the tips Even if they go "Ok I think this is a bad idea, but if you're going to do it..."

 

Thanks again,

Kyle

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Does anyone know the glide ratio of a Cozy Mk IV?

Engine out, prop stopped, figure on 13:1. Some folks will quote you 16:1, but that's with the engine at idle and the prop turning.

 

Also you need pressure breathing above FL280 so you could push your altitude up just shy with just oxygen.

Assuming you could get that high at gross or above, which you can't. Maybe low 20's, after an hour of climbing.

 

Second, has anyone tried taking off over gross weight?

Do you think that we'd admit it in a public forum if we had, since it's illegal without a waiver from the FAA?

 

Now hypothetically, if a person were to attempt a takeoff at ~6000 ft DA at 2200 lb. in a 180 HP COZY MKIV at a mid-CG, I could be pretty sure that it would take about 4000 ft. of runway to break ground, and that the EVENTUAL climb rate, after about 15 seconds of acceleration, might be around 700 fpm.

 

What is anyone's best guess of the runway needed for 500lbs overweight (infinite?)

First, define the Density Altitude, and what you believe Gross Weight to be. Do you have a climb prop or a cruise prop (or a CS prop)? How much HP? Where's the CG?

 

So, right out of my butt: 180HP fixed cruise prop, SL Standard Day, 2050 MGW, rear CG - Nat's plane, essentially - 6000 to 8000 ft. would get you off the ground with a few hundred fpm climb rate. Maybe.

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So, right out of my butt: 180HP fixed cruise prop, SL Standard Day, 2050 MGW, rear CG - Nat's plane, essentially - 6000 to 8000 ft. would get you off the ground with a few hundred fpm climb rate. Maybe.

My wild assed guess would involve a (couple of) simple test(s). Check your takeoff distance at 1800#. Check it again at 2200#. Take the ratio of distances (say 1.3) and square it. Use the result against the 2200# distance to get your 2600# distance. If you gather data at, say, 1500#, 1800# and 2100# you might verify the validity of the math (again, it's a SWAG).

 

As to over gross operations, when my wife and I went cross country, we regularly launched in our Long-EZ in excess of 1600# and close to 1700# a few times. That's an O-235 against a 1325# design gross and 1425# design over gross IIRC. If you've got a long enough runway (>4000?) and low enough DA (<3000?) you should be OK. We used a lot of runway and had anemic climb but I was aware of all that going in and was appropriately cautious (like retracting the nose gear as soon as I rotate, and don't over-rotate. Just remember to avoid hard landings and real hi-G maneuvers at really high weights.

 

Overweight operations are a lot like high DA ops except that high DA is more dicey IMO. DA / excess thrust issues have been part fo my life for a long time. I'll take overweight with a good engine/prop every time.

 

Definitely work into it gradually. Go coast to coast a couple of times before you trans-Pac. Then it's off to Australia.

 

Jim Sower

...Destiny's Plaything...

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