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SunCoastSkydive

Skydiver input needed: New skydiving aircraft launching 2012

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I'm sorry but those NewZealanders have already beaten you to it.

The PAC750 already ticks all of the boxes. There are two of them in the UK. One at Cark, and one at Hinton IIRC.

It climbs fast, has lots of seats, carries 17 skydivers + pilot, has a reasonably sized left hand door, and enough handles and grips for anybody.

The only improvement you could make to the PAC750 is probably to uprate the airframe for more passengers.

The only minor issue with the PAC750 is the low wings. And seemingly close tail plane.

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Again, I'm new back to the sport after a lengthy layoff - I have scratched my head a few times the past few weeks when seeing DZ statements about their PAC750 jump planes as "the only plane designed for skydivers". While the performance attributes look good, that low horizontal skydiver magnet behind the door suggests otherwise (IMHO).

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PAC750 jump planes as "the only plane designed for skydivers". While the performance attributes look good, that low horizontal skydiver magnet behind the door suggests otherwise (IMHO).



No, your HO is correct. The PAC is an update of a plane called a Cresco. It shares the same basic airframe with the Cresco, but has an updated engine, panel, and a host of improvements. They sell a version of it designed for skydiving in that it comes new with a jump door, steps, handles, no interior, etc. So in a sense, it is a 'new' plane, and it was built for jumping, but the airframe itself was not designed with jumping in mind.

All that aside, since they made those claims, there is another 'new' plane that can be bought with a jump configuration, the Kodiak. It's similar to a Caravan, and can be ordered set-up for jumping. It was not 'designed' for jumping, it was designed to be a versitle, STOL aircraft (like the Cresco), and it just so happens that jumpers like verstile STOL aircraft. So they outfit it for jumping, and it's a 'new' airplane built for jumping.

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The PAC750 already ticks all of the boxes.



I'm not sure which boxes you're talking about, but my requirement set doesn't include "small door", "cramped cabin" or "CoG issues when launching an 8-way". It may have some useful performance characteristics for dropzones, and for certain types of skydiving, it may be great, but for a lot of the things that I do most of the time, the PAC750 is not well suited at all.

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For a single engine plane its pretty decent.

The only thing that comes close is the Grand Caravan, which carries 4/5 less skydivers. and the door is pretty small on those things too but the wings are high up and the tail a bit farther away.

Below that you've got, the SMG turbo finish which is horrifically cramped, then Porter Pc6 (one in the UK) which is again horribly cramped, then airvans and then 206s and 185 cessnas.

For anything bigger and better cabin and doorwise you're going to have to go for a twin engine like the Dornier G92s, twin otters, Islanders etc. I learnt on the G92 big big door on that, but it's run in speed is too high for my liking.

Off my head over here in England there are only a couple of DZs that use twin engine planes. Dunkeswell uses a Twin beech, Hibaldstow uses a G92, A few London DZs use twin otters and Islanders.


And twin engines for what I know probably cost a lot more to run than your single engine setups.

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The only thing that comes close is the Grand Caravan



Grand Caravans (and 'regular' Caravans!) are horrible in my book. They're relatively slow, they're generally uncomfortable to ride in and they have very limiting C of G rules. Unfortunately more and more UK DZs have been adopting them, and you're absolutely right - it all comes down to the cost. It's very hard to argue against that single-engine benefit.

G92s are actually among my favourite jumpships - fast, with a big door and easy to launch from - but it comes down to how they're flown. I think the force of the slipstream isn't so much to do with the run-in speed as the propwash. If the pilot can reduce the power on that side during climbout and fly the aircraft out of trim, then it makes a big difference.

I haven't jumped a PAC 750 - but that low tailplane does look a little intimidating, and I think gives away the fact that it's actually an adaptation rather than a purpose-designed skydiving aircraft. I think the PAC has pretty stringent C of G rules too, doesn't it?

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I think I need to echo a prior poster: if you're building a "purpose built skydiving aircraft" and its got a side door, you're not purpose building a skydiving aircraft.

In a perfect world, when you get what you want, the way you want it, thats the way you'd have always exited aircraft.

Could you build a car with a trunk lid that only was accessible from one side? Sure, but why would you?

Same goes for a purpose-built skydiving plane.

The bigger problem seems to me that building a purpose-built skydiving plane in Oz has already been done, so you had better offer some key differentiators or you're not going to make much of a dent in a market that already doesn't have a lot of "dentable space." If you can't appeal to the operators, you're screwed. Skydivers, while picky SOBs, don't buy the plane or operate it and have to make a business case out of purchasing a new plane from 10,000 miles away.

That would be like asking me what my preferred UPS truck looks like. I dunno, how about the one that gets the packages to me *instantly*? The bean counters are UPS are going "nooooO!"

What are some key differentiators that you should be going for?

a) Tailgate. People want tailgate aircraft. 90% of the aircraft in the skydiving world are side exit airplanes. You're going to be joining a long list of planes with a side exit, so the rest of your differentiators better be good. So, here are some other things you need to stick out if you stick with a side-exit:

b) Low cost per head per jump. Lower per-head costs means you can fly the plane fully loaded and make $$. If my per-jumper per-load cost was, say, $17 in a Twin Otter, then the plane that works out closer to $14 a head is far more attractive. If I can make $3 more, maybe I don't raise my price, or I can absorb better fluctuations in the cost of JetA.

c) Easy to maintain and operate. Single-point hot refueling capability, don't put the filler neck/single-point a foot from the prop arc, etc. Make a durable interior that doesn't have to be fixed with duct tape every 2 weeks.

d) Related to b), but cheap to operate. You're already there with PT-6s (industry standard). Add FADEC and "push to start" to allowed computer-controlled starts instead of complex hand-jives in the cockpit. Lessens your chance of a hot start. How about making the engines easily accessible, so you're not blowing shop money taking the cowlings off.

e) eye-level windows for the folks inside if they're on benches. I hate ducking to see out.

f) Steps, floater bars, avoidance of pinch points, snags, things like the flap mechanism on the Otter, etc

thats off the top of my head.. undoubtedly there is more.

Operators, they really need to hear from you on this.
NIN
D-19617, AFF-I '19

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If you can't appeal to the operators, you're screwed. Skydivers, while picky SOBs, don't buy the plane or operate it and have to make a business case out of purchasing a new plane from 10,000 miles away.



That's a great point. Look at some of the shit planes that people jump out of as proof. Look at some of the shit planes that people will drive for hours and spends $100's/weekend to jump out of. Jumpers will take anything that's flying and 'safe'.

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Tailgate. People want tailgate aircraft. 90% of the aircraft in the skydiving world are side exit airplanes



A tailgate is one of the few 'draws' out there these days. Jumpers will travel further and spend more on a tailgate, but I think it's more than just the back door that brings them.

Being able to stand-up in the plane, and being able jam 4/5 across the door is a big part of the Skyvan/Casa appeal. Both of those require a tall and wide cabin, and that requires two big, thirsty engines.

If you were looking to produce an 'ideal' skydiving plane, it would be a single and haul 12-14 jumpers per load. It's not as much as an Otter, but there are more DZs that cannot support an Otter than can, so smaller is the way to go. If you built a 12 place tailgate with an Otter height cabin and a door that could fit two-across, I have a feeliing that tailgate would be less of a 'draw', than the bigger tailgates.

The truth of this whole issue might be that VPR has the right idea. A PT-6 powered 206 just might be the 'ideal' skydiving aircraft. They're looking to be cheap enough that a DZ needing two 182s could afford one, and you could buy two of them and still be less than the cost of 'normal' turbines. Cheap to buy, fast turn around, and the ability to haul 3 tandems or two AFF lv 1's means a DZ can use to 'make money', and the fast turns means that can work the fun jumpers in there as well.

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What are some key differentiators that you should be going for?

a) Tailgate. People want tailgate aircraft. 90% of the aircraft in the skydiving world are side exit airplanes.
b) Low cost per head per jump.
c) Easy to maintain and operate.
d) Related to b), but cheap to operate.
e) eye-level windows for the folks inside if they're on benches. I hate ducking to see out.
f) Steps, floater bars, avoidance of pinch points, snags, things like the flap mechanism on the Otter, etc


a)not necessarily tailgate, what jumper want is bigger-better-faster than what they usually jump. Skydivers are pussies. They want to be able to jump in bigger groups, with a silent and fast and comfortable plane. If you are used to jumping a TwinOtter for example, you might want a tailgate. For us Porter jumpers, we are already very happy with a Twin Otter.
b+c+d)operators would want all that, cheap, easy to fly and maintain. Jumpers could be happy too because jump ticket price might go down a bit.

The ideal plane would be a widebody tailgate PC12 :)
scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

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How fast is a fast turn around? And does it take into account the time it takes to get down?

The PAC750 DZ I jump at the plane comes down slowly, that said their jump turn around is sometimes painful. They are so laid back and easy going it gets frustrating sometimes. On a blue sky morning in three hours with four full manifests they managed three lifts.

While their major competitors 40 miles south use a Turbo PC6 yet they manage 4/5 lifts per hour @ 14000ft Plane goes up, and dives and lands. The porter often beats the skydivers to the ground it comes down so quick. They can back to back lifts so quickly that one tandem instructor can freefall. Land rip his rig off put another one on and hop on board just as the plane turns round to line up for the runway.

The camera guys with 3 rigs have been known to back to back 3 lifts.

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I was told once that the PC6 has a trap door in fact looking at this:

http://www.airbornetechnologies.at/fileadmin/user_upload/sales/preferred/docs/pc6/Pilatus-PC-6-Aerial-Photography.pdf

It does! Maybe they should drop people out of that instead of the sideways door? :P

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How fast is a fast turn around? And does it take into account the time it takes to get down?



See this thread for all the details -
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=3706926;page=1;sb=post_latest_reply;so=ASC;mh=25;

More or less, he's looking at 3 loads per hour including time for fueling and loading. With 350hp and a turbine for fast descents, he's projecting 15 min wheels up to wheels down.

I'm not sure why your PAC takes so long to get down. Piston engines will cool too fast if you climb for 25 min, then pull the power and dive toward the ground. The hot engine combined with the high speed airflow (pitson aircraft engnies are air cooled) can cause cooling to such a degree that the cylinders can crack. So you have to keep some power on to maintain heat, and descend slowly to keep the engine together.

Turbines are not air-cooled, and can maintain more heat in the engines during the descent (and don't have cylinders to crack), so a tubine can dive as fast as the airframe allows. There's no reason that a turbine shouldn't be on the ground before the tandems.

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Not to slide off topic:

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Turbines are not air-cooled



Sorry to correct you Dave, but about 80% of the air drawn in by a PT6 is used for cooling.
Its the way the air is used to cool the engine that leads to shock cooling and cracked cylinders.

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Sorry to correct you Dave, but about 80% of the air drawn in by a PT6 is used for cooling.
Its the way the air is used to cool the engine that leads to shock cooling and cracked cylinders



You are correct. I could have more specifically said that turbines are not air cooled in the same way that piston engines are air cooled, that being through external airflow over the engine structure. For that reason, the super cold air at jump altitude combined with the lack of heat produciton when the power is pulled, aircraft with piston engines need to descend slowly to order to keep engine temps stable and avoid damage.

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Not to slide off topic:

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Turbines are not air-cooled



Sorry to correct you Dave, but about 80% of the air drawn in by a PT6 is used for cooling.
Its the way the air is used to cool the engine that leads to shock cooling and cracked cylinders.
I thought the big ventilator blades we have in front of the plane were used for cooling :S
scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

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>a) Tailgate. People want tailgate aircraft.

I'd disagree there.

Teams don't want them. They get a big advantage by being able to be in the air as they launch. In many cases bigways don't want them - trail planes are harder to coordinate when there aren't a few people who can see the lead plane's people 100% of the time. As an instructor I don't like them - less control over a student before exiting. It's a lot harder to blow an exit from an Otter than from a Skyvan.

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in reply to ">a) Tailgate. People want tailgate aircraft.

I'd disagree there.

Teams don't want them. They get a big advantage by being able to be in the air as they launch. In many cases bigways don't want them - trail planes are harder to coordinate when there aren't a few people who can see the lead plane's people 100% of the time. As an instructor I don't like them - less control over a student before exiting. It's a lot harder to blow an exit from an Otter than from a Skyvan. "
.......................................

Some teams might not like them but they're adaptable.
Diving formations out the back of a tailgater gets you flying pretty quick.
One of the major advantages of a tailgater is that you can be moving before you exit the aircraft.
Not so much a poised exit but more dynamic.
This is useable by teams to actually get flying into the 2nd formation quicker than a side exit , as the momentum input required can be dialled in before even leaving the aircraft.

Watch a good team dive out the back of an tailgater and tell me they're not flying just as quick (I'd say quicker;)) as a side exit.

Big ways need to see out ...put in a window.:S

As an instructor less control over student because why? they can stand up? might want to practice that one.

Lot harder to blow an exit from an Otter than from a Skyvan? , once again practice makes perfect.

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This is a turbine powered Gippsland Airvan, isn't it?



Found a pic. See attached.

(The GA-8 is used by Civil Air Patrol here in the States, and by various missionary aviation groups in Asia and Africa. Its a pretty solid "bigger than a 206, smaller than a Caravan" piston single)
NIN
D-19617, AFF-I '19

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PAC 750 was updated - from Cresco - because the fetilizer industry developed a newer fertillizer that is more bulky, ergo the larger cabin.
Telling skydivers that the PAC 750 was designed specifically for them is purely a marketing ploy.

Similalry, the Quest Kodiak was designed to help Christian missionaries access the deepest, darkest jungles where natives have never heard the word of Jesus.
The fact that the Kodiak is far better at short-field/short-lake operations is the primary goal. The fact that it climbs better than a Caravan is a pleasant side-effect for skydivers.
Again, skydivers were near priority-last when Quest was designing the Kodiak.

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You clearly haven't been at Cark when they've been busy then! I was there for a 4-way competition a few years ago when they completed the entire 6-round competition with about 15 teams all in one day out of 1 aircraft, and even managed to fit a few tandems and fun jumpers in as well. I think they managed 35 lifts that day. The Pac750XL will dive freakin fast when they want it to!

Yes on a day-to-day basis they can occasionally be slow, but as you say that's just the laid back nature of Cark. And in my opinion it's an awesome place to jump!

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Except Cark is my Home DZ. I have only been there about 9 months though and work has kept me away. from the busy periods they have, I missed the open week! Cark is a bugger to get to is.

I've seen the laid backedness of it all, I agree it is a good place to jump bar the cow pats EVERYWHERE in summer :D

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