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Posted

I am looking at a 1979 mooney rocket for sale on controller.com that does not have the long range tanks. Any idea it costs to install those? I am thinking it will be a significant amount because of wing work etc...

http://www.controller.com/listingsdetail/aircraft-for-sale/MOONEY-M20K-231/1979-MOONEY-M20K-231/1270275.htm

Thanks

Wow, they are giving that rocket away... Probably due to motor time or the two gear ups?

Sorry, don't know how much long range tanks would cost, but I'd guess its about 8K. That's what a bladder install runs.

Posted

There is another one with a gear up for less than 100k, however, this one has a much higher useful load.

Actually now that I think about it, we always want a break after 2-3 hous of flying .. so maybe the long range tank is not that big a deal .. but it would be nice to have that option.

Btw vref prices that aircraft at 99k despite the rocket mod.. its cheap mostly because of the number of hours flown etc, as far as I can tell.

Posted

Man, that is a lot of airplane for the money. Love the extended baggage compartment and fold down rear seat mods by LASAR. It looks like this Rocket was originally a very early '79 231 that does not have built in oxygen. Just something to be aware of.

Jim

Interesting. Thanks for the heads up. Did they start having built-in oxygen after a certain model year?

Posted

Other than aesthetics, what does the built in system get you over the portables? I've never used a built in system in a civilian aircraft

Posted

Other than aesthetics, what does the built in system get you over the portables? I've never used a built in system in a civilian aircraft

Germs, dirt, pollen hiding in the system

Posted

Mostly the built in system is convenience. Much of the lines, etc. are enclosed, and you don't have to fiddle with where to put the tank, or move it for passengers. Once you have it installed, I don't think the cost of upkeep would be any different than a portable unit. But my guess is that the cost of getting a system installed would quickly drive you to a portable rig.

Posted

To be perfectly honest, I don't remember what the 5 year(?) certification costs, but my guess would be that technically, your portable tank would require the same certifications.

Posted

To be perfectly honest, I don't remember what the 5 year(?) certification costs, but my guess would be that technically, your portable tank would require the same certifications.

I am seeing around 2000 unless you get a carbon fiber tank, then those are good for 15 years apparently. But I am guessing you still need to recertify valves etc in a shorter period.

Yes the convenience of not having tubes around is certainly nice .. Not to mention accidentally unplugging somebody by shaking a line loose or something (if thats possible to do)

Posted

I think the other big thing in favor of portables is the ability to recharge it anywhere (most medical places or dive shops etc) .... I think.

Posted

 The Rocket engine burns 15 gallons/Hr in cruise. Add to that 20 gallons on the climb and you end with four hours endurance. The advantage of the extra power is obviously the speed. The added speed is more significant on long trips. On a M20J a 900nm trip will take 6 hours while on the Rocket at 200Kts will take 4,5 hrs. But if you do not have the extra fuel you will need to stop for refuel,  that takes away the speed advantage. The Acclaim that uses 300HP engine has 100 gallons standard (130 with LR Tanks). This gives you an idea why having the extra fuel. Check with Monroy for your installation options.

 

I have portable oxygen for some of my flights. The advantage of portable is cost and filling options. I found more Scuba Dive shops on the Caribbean Islands than FBOs with oxygen. And these dive shops are usually attended by a nice girl in bikini. Call ahead to make sure they have Nitrox (nitrogen and oxygen) capability. Your tank will be filled from the oxygen tank only. Typical rate is $15 per fill vs $90 at an FBO. But if you are flying to Olathe Kansas don't expect any girls in bikini. A drawback of the installed oxygen is the payload penalty whether it get used or not. With the portable you can leave the tank in the hangar for added payload.

 

José      

  • Like 1
Posted

The FAA says only aviation grade oxygen should be used apparently. I wonder why or maybe the FAA wants to certify god's work ...

Are the lungs in a pilot different than those in Scuba diver? I have used dive shop oxygen for over ten years and never had any issues. Just make shure the shop has Nitrox (Nitrogen and Oxygen) capability. Typical refill is $15.

 

José 

Posted

I heard once that medical O2 had more moisture in it than FAA certified O2, maybe wrong but if it did it could cause a valve problem in below freezing temps.

That seems to be old news, since its cheaper to add moisture at the patient's bed side rather than in the tanks. Apparently now all tanks just carry pure oxygen with the welding supply oxygen being the most pure.

The easiest thing to do seems to be to lease huge cylinders from praxair and refill the portable tanks from those. When the cylinder empties praxair or airgas delivers new filled cylinders. Lease cost is 160 for 5 years ( one data point, varies with region a bit) plus filling cost which is about 25 or so per 300 cu ft bottle.

Posted

Can someone comment on Nitrox.  The comments here are to be sure the scuba shop has that capability.  Does that imply that he combination is somehow beneficial?  The other comment is that "your cylinder will be filled from the oxygen tank only," implying you do not want nitrogen in the mix.

 

John Breda

Posted

Nitrox is just compressed air with oxygen added. The scuba shop will have an oxygen tank they use to add the additional oxygen to the air tanks.

What they are saying is don't put compressed air in the aircraft tanks, just oxygen.

Posted

Can someone comment on Nitrox.  The comments here are to be sure the scuba shop has that capability.  Does that imply that he combination is somehow beneficial?  The other comment is that "your cylinder will be filled from the oxygen tank only," implying you do not want nitrogen in the mix.

 

John Breda

Normally Scuba dive tanks are filled with just plain air (80% Nitrogen and 20% Oxygen). But for extended deeper dives the ratio of N/O needs to be adjusted to avoid oxygen intoxication, which is due to the increased partial pressure of oxygen due to water depth pressure. By using Nitrox at different ratios the diver can stay longer and deeper. There is no flying benefit using Nitrox. Pilots only use oxygen. The objective of finding a dive shop with Nitrox capability is to fill your oxygen tank from the oxygen tank only at the dive shop. Unlike filling an installed tank the portable tank gets submerged in water while filling to keep the temperature down. This insures full pressure when you get the tank back to the plane and makes filling quicker. An installed tank filling may take an hour to allow some cooling. But what is worse is the pressure drop at altitude due to temperature. Keep in mind that the installed tank is out in the tail cone subject to temperatures below zero. So you loose pressure, even without using it.

 

José 

  • Like 1
Posted

 The Rocket engine burns 15 gallons/Hr in cruise. Add to that 20 gallons on the climb and you end with four hours endurance. The advantage of the extra power is obviously the speed. ... But if you do not have the extra fuel you will need to stop for refuel,  that takes away the speed advantage...

José      

Another way to compute range is to multiply max seat time (I'd estimate about 3.5 hours for me) times speed.   In the "C" that comes out to about 450-500 nmi.  There's still >15 gallons aboard at that point but I'm ready to get out of the plane.

Posted

 The Rocket engine burns 15 gallons/Hr in cruise. Add to that 20 gallons on the climb and you end with four hours endurance. The advantage of the extra power is obviously the speed. The added speed is more significant on long trips. On a M20J a 900nm trip will take 6 hours while on the Rocket at 200Kts will take 4,5 hrs. But if you do not have the extra fuel you will need to stop for refuel,  that takes away the speed advantage. The Acclaim that uses 300HP engine has 100 gallons standard (130 with LR Tanks). This gives you an idea why having the extra fuel. Check with Monroy for your installation options.

 

Jose', your assumptions are off on Rocket fuel burn.  It will do 15gph and it will easily do 200TAS, but both not at the same time.  Also it runs 32/33 gph on 100% power climb setting, which I run usually for maybe 60 seconds and then cruise climb at 27gph - you see book is 1600fpm and 1450fpm resp which is pretty close to what I get for climb.  Nice thing is at that rate you don't climb for so long so 27gph doesn't last all that long.

  • Like 1
Posted

Another way to compute range is to multiply max seat time (I'd estimate about 3.5 hours for me) times speed.   In the "C" that comes out to about 450-500 nmi.  There's still >15 gallons aboard at that point but I'm ready to get out of the plane.

 

I like that system.  So a rocket without long range tanks is a ~700-750 machine.

 

I have a rocket w/o long range tanks.  For now, with my 3 boys still at home, I like the weight and balance more than the extra fuel.  I suppose eventually someday I might get LR tanks but for now, I really don't miss it.  There are exactly 0 flights so far where I would have really wished I had them so far - but that could change in the future.  For now, I tend to fly airlines if we are talking ~1000mi+....since usually I am on a work schedule and GA and long range flights and schedules seem to self contradict in my experience. The farther distance I fly the more I tend to want to delay, divert, fly around, due to weather.

 

I am curious, how many of you folks with LR tanks actually make flights that rely on those long range tanks, and if yes, how often in terms of percentage of your flights?

Posted

I am looking at a 1979 mooney rocket for sale on controller.com that does not have the long range tanks. Any idea it costs to install those? I am thinking it will be a significant amount because of wing work etc...

http://www.controller.com/listingsdetail/aircraft-for-sale/MOONEY-M20K-231/1979-MOONEY-M20K-231/1270275.htm

Thanks

 

Wow!  What a deal - is it for real?  Too attractive not to make a call and possibly a pre buy.  Maybe its just a motivated seller.  My guess is that rockets are way undervalued in these times of expensive fuel and expensive overhauls.  If that engine has been flying regularly then it is probably mid-time motor.  If it has been sitting, then factor in an overhaul really.  I see no top - and those continentals and tops....see my top thread as I am almost done with a cylinder top for my rocket - should be flying beginning of next week with shiny new cylinders!

 

Maybe just with an expensive to overhaul engine, expensive fuel these days, that rockets are scaring off folks sort of like the way twins do?

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