A Quick Question About Which Airplane to Purchase
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A Quick Question About Which Airplane to Purchase
Hello guys!
I am looking for a single or multi-engine prop airplane that can carry around a 1,200lb payload ~550-650 nm with full fuel.
I don't know if I am missing something, but I have not been able to find a good method for calculating range under payload from maximum range.
In your experience, which planes would you recommend that fit these specifications?
Thanks!
I am looking for a single or multi-engine prop airplane that can carry around a 1,200lb payload ~550-650 nm with full fuel.
I don't know if I am missing something, but I have not been able to find a good method for calculating range under payload from maximum range.
In your experience, which planes would you recommend that fit these specifications?
Thanks!
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Well if you were on this side of the pond I would try and sell you my PA28-235. Empty weight 1628 lbs. MTOW 2900 lbs. Fuel capacity 84USG. Range at 120kt cruise about 750nm without reserves. I'm sure there are several available in the US.
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Lysander, just as a matter of interest, is that the average consistent cruise you get out of the 235 and do you know if the 236 is any faster ?
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Thanks for the response!
I guess I worded my post incorrectly, I am looking for a Fully Fueled Payload of around 1200 lb.
If I am not mistaken, range drastically decreases the closer you get to the payload max, correct?
I guess I worded my post incorrectly, I am looking for a Fully Fueled Payload of around 1200 lb.
If I am not mistaken, range drastically decreases the closer you get to the payload max, correct?
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120 is my normal cruise to get the right balance of speed and consumption. It will happily cruise along at 130, but it's very thirsty at that, even leaned properly.
I have no experience with the 236 I'm afraid, but I can't imagine it would be too different.
I have no experience with the 236 I'm afraid, but I can't imagine it would be too different.
Not difficult at-all, just time consuming.
Take the W&CG report and POH, run a flight profile for a zero wind cruise for a series of conditions. I'd suggest the following cases, using a representative power setting - something around 65% / 8000ft is probably good for best range if a better value isn't declared in the manual):-
(1) 1 pilot, max fuel, no baggage, minimum take-off, taxi, and reserve fuel
(2) 1 pilot, max fuel, bagge to MTOW, same constraints
(3) 1 pilot, 75% fuel, baggage to MTOW, same constraints
(4) 1 pilot, 50% fuel, baggage to MTOW, same constraints
Get a bit of graphpaper (or use Microsoft Excel in this day and age) and plot the four points on an axis of bagge weight versus useable still-air range, then the best smooth curve you can through them.
You now have a curve of realistic range versus payload.
Do this for two or more types, and you have a realistic comparison. This is probably a day or two's work and requires a bit of running about, and gathering data. But given the financial investment of an aircraft in this sort of bracket - well worth the effort. Of course, to some extent there'll be degredation in performance of all aeroplanes from new and/or perfect flying in flight test - but at first approximation, you can reasonably use published data for direct comparison between types.
G
Take the W&CG report and POH, run a flight profile for a zero wind cruise for a series of conditions. I'd suggest the following cases, using a representative power setting - something around 65% / 8000ft is probably good for best range if a better value isn't declared in the manual):-
(1) 1 pilot, max fuel, no baggage, minimum take-off, taxi, and reserve fuel
(2) 1 pilot, max fuel, bagge to MTOW, same constraints
(3) 1 pilot, 75% fuel, baggage to MTOW, same constraints
(4) 1 pilot, 50% fuel, baggage to MTOW, same constraints
Get a bit of graphpaper (or use Microsoft Excel in this day and age) and plot the four points on an axis of bagge weight versus useable still-air range, then the best smooth curve you can through them.
You now have a curve of realistic range versus payload.
Do this for two or more types, and you have a realistic comparison. This is probably a day or two's work and requires a bit of running about, and gathering data. But given the financial investment of an aircraft in this sort of bracket - well worth the effort. Of course, to some extent there'll be degredation in performance of all aeroplanes from new and/or perfect flying in flight test - but at first approximation, you can reasonably use published data for direct comparison between types.
G
Last edited by Genghis the Engineer; 8th Dec 2014 at 21:21.
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mandolino
the easy way to do it is this way...1200 pounds of payload is about 6 pax with bags (and that is if they are slender pax)
so, look at 8 to 10 seat planes as your pax will probably be a little fatter and its better in this case to look at a bigger plane
now, I won't tell you what kind of plane to get...but a seneca or cherokee six/saratoga will probably be too small, so go bigger.
the easy way to do it is this way...1200 pounds of payload is about 6 pax with bags (and that is if they are slender pax)
so, look at 8 to 10 seat planes as your pax will probably be a little fatter and its better in this case to look at a bigger plane
now, I won't tell you what kind of plane to get...but a seneca or cherokee six/saratoga will probably be too small, so go bigger.
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I don't see enough specs to recommend really, but it is truely a matter of reading POHs and do math on your own. Safe 1200@FF over 650 could well be in a regime where relatively big GA birds like C208 fly.
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With those numbers the market is not all that large. At a minimum you'd be looking at a GA8, which just barely makes your numbers (with full fuel you have a usable payload of about 460 kg, and a range of about 700 nm). The next step up from that would be a C206 or similar, or a pretty significant twin (Cessna 414 comes to mind).
Are you a pilot? Range doesn't decrease magically and drastically when you are close to payload max. Range simply decreases because at some point you've got to make a tradeoff between taking more fuel (which increases range) and taking more cargo/pax (making more money). If your aircraft is at MTOM but you don't have enough fuel on board to make the required range, you need to offload cargo/pax to make room for fuel. Simple.
In the GA8 example, the fuel tanks can hold 332 liters of Avgas, which weighs 0.72 kg/l. That's 239 kg that's eating into your usable payload (of about 700 kg) when you fill the tanks to the brim. Take less fuel, your range reduces but your usable payload increases. That's all there is to it.
Sure, a heavy plane (loaded close to MTOM) requires more power, and thus more fuel, to stay aloft compared to the same plane with a lighter load. However, at the lighter end of the GA spectrum, that effect is almost never taken into account. All the cruise performance numbers you'll find are based on MTOM configurations, as most of these planes will actually fly near MTOM most of the time.
Oh, and in your payload calculation, don't forget to include the weight of the pilot. That can easily add another 200 lbs.
If I am not mistaken, range drastically decreases the closer you get to the payload max, correct?
In the GA8 example, the fuel tanks can hold 332 liters of Avgas, which weighs 0.72 kg/l. That's 239 kg that's eating into your usable payload (of about 700 kg) when you fill the tanks to the brim. Take less fuel, your range reduces but your usable payload increases. That's all there is to it.
Sure, a heavy plane (loaded close to MTOM) requires more power, and thus more fuel, to stay aloft compared to the same plane with a lighter load. However, at the lighter end of the GA spectrum, that effect is almost never taken into account. All the cruise performance numbers you'll find are based on MTOM configurations, as most of these planes will actually fly near MTOM most of the time.
Oh, and in your payload calculation, don't forget to include the weight of the pilot. That can easily add another 200 lbs.
Last edited by BackPacker; 10th Dec 2014 at 07:57.
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The question is, how much do you have to spend? Also what volume is the payload. What type airfields hard/soft length you need to operate into.
Most 200/220hp 4 seat aircraft can lift 950/1200 lbs including fuel.
That's a Cessna 177RG or FG 180hp to a 182 which needs more fuel so the usable pay load is the same.
With the requirement you have specified I think 300 plus HP would be needed and six plus seats. Some of the big Robins/Jodels can lift impressive loads more than their weight or a twin with at least 200hp a side would be needed if not more.
A Britain Norman Islander might do it but may be slow or range limited.
Most 200/220hp 4 seat aircraft can lift 950/1200 lbs including fuel.
That's a Cessna 177RG or FG 180hp to a 182 which needs more fuel so the usable pay load is the same.
With the requirement you have specified I think 300 plus HP would be needed and six plus seats. Some of the big Robins/Jodels can lift impressive loads more than their weight or a twin with at least 200hp a side would be needed if not more.
A Britain Norman Islander might do it but may be slow or range limited.
