And so what if a Super Otter doesn't climb faster than a PAC 750 with one engine inoperative. How fast does the 750 climb with one engine inop? Yah... not so great is it?
How fast does a -27 twin otter climb with 23 jumpers, a fresh load of fuel, and DA at 10k or so? Not so great either? And you have a pilot getting to deal with a twin running on one engine, which is exciting on it's own!
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4 jumpers as a full load? Say what?! Uhh... that's goverment waste for yah.
Call it what you want, but it was and is done for safety reasons. They must be able to maintain a 50 ft/min climb rate during an engine out scenario, so temp and fuel load regulated how many jumpers we could put on board and still maintain that 50 ft/min climb rate should an engine shred.
Don't get me wrong, I would much rather have a twin otter for a jumpship, but the pac is really not all that bad!
Not to mention AFAK you need 2 pilot to fly a twin engine turbine plane. I look funny on take off when one pilot was handling the controls and the other was keeping throttle and feather in hand. :)
That is just wrong, I never see two pilots in a TWIN Otter, and I am in them a lot.
Call it what you want, but it was and is done for safety reasons. They must be able to maintain a 50 ft/min climb rate during an engine out scenario, so temp and fuel load regulated how many jumpers we could put on board and still maintain that 50 ft/min climb rate should an engine shred.
Don't get me wrong, I would much rather have a twin otter for a jumpship, but the pac is really not all that bad!
Safety? So why are you saying the PAC is "not all that bad"? If the PAC loses the engine it's coming down. With a Twin Otter and a properly trained, current pilot things are a lot better. I've lost an engine in singles and Twins (3 each type). I'll take the twin otter any day.
Safety? So why are you saying the PAC is "not all that bad"?
I never said I agreed with those practices...they are just the policies set by the air force academy for jump operations with their twin otters.
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If the PAC loses the engine it's coming down. With a Twin Otter and a properly trained, current pilot things are a lot better. I've lost an engine in singles and Twins (3 each type). I'll take the twin otter any day.
So are you saying that a full otter...i.e. a -27, 23 jumpers, couple loads of fuel...on a hot summer day would have no problems maintaining alt? Hell, I'm no pilot, so I just go off of the pilots I've worked with, but the impression I've gotten is that in that situation, one or no engines, the bird is coming down!
(This post was edited by Miami on Jan 22, 2006, 6:31 PM)
Safety? So why are you saying the PAC is "not all that bad"?
I never said I agreed with those practices...they are just the policies set by the air force academy for jump operations with their twin otters.
In Reply To
If the PAC loses the engine it's coming down. With a Twin Otter and a properly trained, current pilot things are a lot better. I've lost an engine in singles and Twins (3 each type). I'll take the twin otter any day.
So are you saying that a full otter...i.e. a -27, 23 jumpers, couple loads of fuel...on a hot summer day would have no problems maintaining alt? Hell, I'm no pilot, so I just go off of the pilots I've worked with, but the impression I've gotten is that in that situation, one or no engines, the bird is coming down!
Good grief,
I am no expert, but if either losses an engine I am getting the hell out!! Not only to save my own ass, but to reuce the weight of the aircraft to give the pilot a fighting chance to land the aircraft!!
Please refelect back to what the original post was, it was a very simple question. Pac750's and Otters are both AWESOME aircraft. The both have their benefits and drawbacks.
I get the benefit of jumping the PAC, Otter, KA and Beech99 all with in an hour from my home, oh and the 182 during the week . They are all fun jump planes and they all ahave their place in our sport. Some are cheap, some are expensive, some are VERY fast, others are VERY comfortable, Etc. Etc.
Not to mention AFAK you need 2 pilot to fly a twin engine turbine plane. I look funny on take off when one pilot was handling the controls and the other was keeping throttle and feather in hand. :)
That is just wrong, I never see two pilots in a TWIN Otter, and I am in them a lot.
I have not seen an Otter or L-410 flown by a single pilot.
That may be something specific to the requirements set forth by the aeronautical regulatory agency in your country. In the USA, only one pilot is required for a twin otter.
The only other common plane I know of that requires two pilots in the USA is the CASA.
Have you seen what the climb rate of a -27 super otter is with 23 jumpers and 1 engine on a hot summer day? It really isn't that much better (where are those really smart pilot types to give the precise data?). This was the reason we often had to fly our otter with 4 jumpers as a "full load" at the air force academy...had to be able to actually maintain a climb rate if an engine went down. Not mention what happens when one engine is lost on a twin a/c...makes things really interesting. With a single engine a/c it may be a glider, but gliders are pretty easy to land.
Does the PAC get its great climb rate from a big engine or a big wing (or both?) It looks like a better glider than an Otter or a Skytoaster (err, van).
And with the paint job used for Skydance's original Pac, a great looking plane that can compete with the suits jumping out of it.
Does the PAC get its great climb rate from a big engine or a big wing (or both?) It looks like a better glider than an Otter or a Skytoaster (err, van).
I have no idea, but it does climb quick! Don't know about the gliding part, but either one I would rather be outside the thing if that happened.
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And with the paint job used for Skydance's original Pac, a great looking plane that can compete with the suits jumping out of it.
Haha, I haven't seen skydance's...I've been jumping the one on the east coast in suffolk.
Does the PAC get its great climb rate from a big engine or a big wing (or both?) It looks like a better glider than an Otter or a Skytoaster (err, van).
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If we compare: power-loading, wing-loading, span-loading and aspect ratio:
C206 PAC 750 TwOtter Skyvan
p/l 12, 10, 10, 8.7
w/l 20.7, 24.6, 30, 33,
s/l 100, 178.5, 192, 192
a/r 7.45, 6, 10, 11.2
Judging by power-loading, Skyvans should climb the best.
Judging by wing-loading, Cessna 206 should climb and glide the best. Wing-loading affects stall speed, which affects best-rate-of-climb and best-glide speeds. The heavier the wing-loading, the faster an airplane has to fly to generate sufficient lift, however that higher speed also means more drag, which increases with the square of the velocity, ergo, heavier wing-loading = greater drag.
Judging by span-loading, Cessna 206 should climb the best. Teehee!
Judging by aspect ratio, Skyvan should climb and glide the best, while PAC 750 should be the worst. Aspect ratio usually roughly equals glide ratio (aka. lift to drag ratio). For example, 2.6 to 1 is the most popular aspect ratio for sport canopies and sport canopies glide about 2.6:1. Similarly, most Cessnas have A/R about 7:1 and glide about 7:1. Competition sail planes have A/R in the 40:1 range and glide about 40:1.
However, all these variables dance around each other. While Skyvans may have low power-loadings and high aspect ratios, they also have really bulky and boxy fuselages, which seriously degrade all other variables.
As for the original question about which airplane would glide the best ... probably the Twin Otter if you feathered both propellers. However, if you have difficulty feathering the propeller on the failed engine, then all twins glide worse than singles.
Yes, PAC 750 looks like a better glider than a Skytoaster ... er ... Skyvan, primarily because it has less drag. A pilot's worst nightmare is being hot and heavy, low and slow - in a twin - with a failing engine. Jump planes spend far more time in that environment than any other type of airplane and even god's gift to aviation has only a few seconds to clean up the airplane if he wants to survive. Accident statistics prove that a pilot needs three times the skill to survive an engine failure in a light twin than in a simple single-engined airplane.
Do skydiving centers hire god's gift to aviation?
In conclusion, skydivers place unrealistic faith in twins being able to fly out of engine failures.
Cool plane, cool DZ. The Otter does have a bigger cabin and bigger door of course, but the PAC is supposed to be more cost efficient to run. I also like the step and handles in the door of the PAC.
Skydance did some mods to the engine or exhaust to make it climb even faster. It can also fly a nice slow jump run.
Does the PAC blow more or less half-burnt jet fuel out its exhaust and onto the jumpers than the Twin Otter's left engine while they're standing around outside the door trying to negotiate loading/exit order with the engine idling?
I know this is a problem that can be 99% solved by policy (i.e. figure exit order out _before_ the plane lands and everyone starts to get in) but I am still curious.
PAC for tandems by far. The side bench seating found in most Otters is crap. Students enjoy the ride and have much lower chances of getting air sick in the PAC due to the large windows. The exits are effortless if you simply slide to a seated position on the floow and present on exit.
nb: The max landing weight remains unchanged at 7125. For most Dzs not an issue, especially the ones I jump at - you often have to land after a couple of hundred feet, re clearance or lack off.
B.
Meanwhile, an airworthiness directive (AD) reducing the 750XL’s maximum take-off weight from 3,400kg (7,500lb) to 3,230kg, issued by the New Zealand CAA on 23 December, has been overcome. The AD was issued after the wing failed ultimate load tests.
A modified wing passed ultimate load testing the day after the AD was issued, Hébert says, and the directive has been revised to restore the 3,400kg take-off weight after operators have modified the wing.
Safety? So why are you saying the PAC is "not all that bad"?
I never said I agreed with those practices...they are just the policies set by the air force academy for jump operations with their twin otters.
In Reply To
If the PAC loses the engine it's coming down. With a Twin Otter and a properly trained, current pilot things are a lot better. I've lost an engine in singles and Twins (3 each type). I'll take the twin otter any day.
So are you saying that a full otter...i.e. a -27, 23 jumpers, couple loads of fuel...on a hot summer day would have no problems maintaining alt? Hell, I'm no pilot, so I just go off of the pilots I've worked with, but the impression I've gotten is that in that situation, one or no engines, the bird is coming down!
I chunked an engine on a -27 otter. End of summer, maybe 85 degrees out. Field elevation of departure was 600 MSL. Blew it at 6,000 MSL. 19 jumpers on board. Climbed to 7,000 and let everyone out. I went to 7,000 because that's just when we got back to the airport. It was still going up at that point.
Rook and Missy Nelson can confirm it. Orly King was on there too.
No two situations are the same but I'm scratching my head on why you can only take 4 jumpers in a super otter in the summer even at COS leaving 6,000 MSL. I haven't flown jumpers there before and maybe it's just a certain time of year they institute that rule but is it every load?
Safety? So why are you saying the PAC is "not all that bad"? If the PAC loses the engine it's coming down. With a Twin Otter and a properly trained, current pilot things are a lot better. I've lost an engine in singles and Twins (3 each type). I'll take the twin otter any day.
Yes but too often in the Skydiving industry we have wet behind the ear pilots and they statisticaly have a much better chance of bringing the ship down in a survivable condition with a single engine A/C.
Or as one the jump pilots I trust most said "Lose an engine on a two engine ship, you've got decisions to make, one engine you just act."
. They are all fun jump planes and they all ahave their place in our sport. Some are cheap, some are expensive, some are VERY fast, others are VERY comfortable, Etc. Etc. 
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