Skydiving platform PURPOSE designed

[Praetorian 1]

Ok so what features would you incoproate into the design of a purpose built drop ship (jump plane what ever you want to call your ride to altitude)

I was BSing with a MechEng gradstudent tonight and he told me about an upcoming assignment;
He has to propose a re-design or new design of a current "craft" boat plane car etc. idealised for a specific purpose. he was going to do a water bomber plane for forest fires. I mentioned skydiving and he like most wuffos said we "dont you just open the door and jump" heres the kicker after I talked with him he mentioned that the highest 10 graded projects get sent to a cad(computer aided design) team and in the past have (once in a blue moon)been bought as "concepts" by various manufactures (rumor is the baha (the pickup/car by subaru) is a child of one such design. Not that I expect this to go anywhere but I told him I would check so:
What features would you want in a purpose built jump plane and why, talil gate? canard layout? highwing vs low wing tail shape..
we discussed it and I mentioned the dif between cessna dropzones and casa/otter planes and he suggested something in between (skyvan size or so)
I threw out some radical thoughts (canard layout for one) side doors and tail gate, bars on the trailing edge of wing to hold on. anything you want/like on an existing plane but the important thing is WHY for the sport for safety for economy use your minds please I told him I'd get him enough that this would be a better project then the water bomber

Good Judgment comes from experience...a lot of experience comes from bad
judgment.

[exwhuffo 0]

bombbay doors. ability to strap several people under the wings. laser guided spotting helmets with night vision. dont forget the drink holders!

[Paige 0]

Tail gate is a must. Once you have it, you'll never wanna go back. Def. have the hang bar like on the skyvan, those are fun

Tunnel Pink Mafia Delegate
www.TunnelPinkMafia.com

[JumpCrazy 0]

-Large door wherever it is
-High horizontal stabilizer to allow safe exits even with a premature deployment
-Fast climb
-Fast descent (think straight down like a porter or mullins plane)
-Low jumprun speed with low risk of a stall
-Good fuel economy
-Low maintenance/cheaper maintenance
-Comfy interior (like a skyvan but not as loud or with as much vibration)

Thats all I can think of for now.

Flying Hellfish #470

[nightjumps 1]

-Slightly smaller than Caravan length, but taller.
-Capacity to hold twelve skydivers (10 way with 2 video or 6 tandems or four AFF Cat A's).
-High Wing.
-Single Engine.
-Tailgate only - emergency side exits; one forward, one aft.
-6'4" interior.
-13,500' in 13 minutes.
-Ability to place nine on tailgate without C/G concerns.
-Cost effective enough for six skydivers to make a load.
-15" GPS LCD screen in rear with lexan protector.
-Two way communications in rear to pilot without headset (push-to-talk) with differentiating light color when pilot is talking with ATC (something different than green, yellow, or red).
-retractable Type 7 safety belts that will automatically ratchet into the wall/floor corner when disconnected (kinda like a tape measure) that are neon colored (so you can do a visual check to ensure everyone has theirs on) with slim-line buckles (to easily slip thru the harness).

[riggerrob 558]

Quote

-Slightly smaller than Caravan length, but taller.
-Capacity to hold twelve skydivers (10 way with 2 video or 6 tandems or four AFF Cat A's).
-High Wing.
-Single Engine.
-Tailgate only - emergency side exits; one forward, one aft.
-6'4" interior.
-13,500' in 13 minutes.
-Ability to place nine on tailgate without C/G concerns.
-Cost effective enough for six skydivers to make a load.
-15" GPS LCD screen in rear with lexan protector.
-Two way communications in rear to pilot without headset (push-to-talk) with differentiating light color when pilot is talking with ATC (something different than green, yellow, or red).
-retractable Type 7 safety belts that will automatically ratchet into the wall/floor corner when disconnected (kinda like a tape measure) that are neon colored (so you can do a visual check to ensure everyone has theirs on) with slim-line buckles (to easily slip thru the harness).

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Ditto, plus ability to operate from a 2,000 grass runway. Install a nose wheel to keep the insurance companies happy.
Ten seats is the optimum size for many DZs.
For that weight and climb rate you will probably need need more than 300 horsepower, ergo a small turboprop engine. For economy of operation and low purchase price, please stick to models that have already been produced by the thousands.
For ground safety's sake, try to put the propeller someplace that even a total loser whuffo can not decapitate himself.
As for rate of descent, dive brakes big enough to prevent exceeding Vne would be nice and link them to the throttle, so you can pull full power or full dive brakes, but not at the same time. Try to make the controls idiot-proof for junior pilots.
Bobsled type benches with seat belts coming out of side walls at waist level.
Give the pilot a bubble window by his elbow so he can look straight down on jump run. Heck, just give him/her lots of windows.
Door/ramp tall enough that AFF students can gracefully stand up for exit. Make the door sill low enough that no extra boarding ladders are required.
Also make it easy to hot-refuel.
Give it such a long tail moment arm that even a ten-way on the ramp edge cannot unbalance the airplane.
Finally make it easy to fly for the junior pilot flying his 25th load on a hot, turbulent day of dodging clouds and putting up with obnoxious skydivers.

[nightjumps 1]

Quote

Give the pilot a bubble window by his elbow so he can look straight down on jump run. Heck, just give him/her lots of windows.

What about including a floor window - like some helicopters use?

[calphoto 0]

Basically a Twin Otter or a Caravan with a ramp. The ultimate adaptation would have twin booms coming back from the wings, ending in twin vertical tails and a very large elevator located very high. That would prevent the elevator getting washed out by the downwash from the wing, allowing for slow flight. It would also give much more elevator authority, allowing for a wider CG envelope, plus put the tail above jumpers in the event of a malfunction.
Give the DHC-6-400R (ramp) a glass nose for pilot spotting, and the biggest PT6's you can hang on the structure. The Twin Otter is already the best when it comes to short field operation (short of a C130)
For the Caravan, give it a short field wing. The current Caravan loves it's runway, and is basically unsuitable for fields under 3000' paved. Cessna optomized the wing for cruise. Give it a big fat wing like the Twin Otter.
I think that Pratt and Whitney has a 1600hp PT6 that they put in one of the pilot trainers. That would look REAL nice on the nose of a Caravan.
LOVE the ideas of the neon seatbelts (since we are going this far, possibly with engagement lights/indicators on the pilot's up front display?), GPS display for the jumpers (maybe with a video briefing system for newbies on the way up?), easy communication between the back and the front, and might I also add a good PA system as part of the ROCKING sound system...
Good ventilation for those jumper-induced pollution fronts that seem to form above 5000' MSL?

Hartwood Paracenter - The closest DZ to DC!

[billvon 2,417]

>-6'4" interior.

I think you only need the 6' interior within 2-3 feet of the door. The rest of the aircraft could be Otter height. I like tailgates, but if you want teams to train there you pretty much have to have a side door available as well.

I've often thought the C-119 design with updated engines and an additional side door would be the ideal general-purpose jump aircraft for a large DZ. Boom tails. high horizontal stab, no interference from structure near the doors. For smaller DZ's, i think a Caravan is pretty close to ideal, since most teams still prefer a side door to a tailgate, and AFF exits seem to come off a bit smoother. Plus which they are available used. New aircraft specifically designed for skydiving are nice, but we'd never be able to afford them until they were used, and if they are specific enough that no one else will buy them there won't be any used ones available.

For big ways I've often thought that something like a PBY with floater bars extending nose to tail would be pretty ideal. Exit in the front, climb to the rear on the bar, then have all 40 people exit at once. Since people crowd into the front during exit, no problems with aft CG.

[gmanpilot 0]

I think the Pilatus PC-12 would make a hell of a jump ship, but they are still too expensive, and they are not approved for flight with the door removed. It would require an STC.

_________________________________________
-There's always free cheese in a mouse trap.

[Andrewwhyte 1]

Fixed gear. It gets used much more than most aircraft and is a major money sucker on King Airs etc.

[rickjump1 0]

Crashworthy seats with a 3 way shoulder harness included with the safety belts(would this be a type7?)In addition build the cockpit and cabin for max crew and pax survival. Why not airbags and seats designed to collapse with high g forces? Yes it's going to get expensive at first. NASA could help.

Do your part for global warming: ban beans and hold all popcorn farts.

[benny 0]

I think you may be going overboard, this is what we have parachutes for!

Never go to a DZ strip show.

[rickjump1 0]

The most critical time in an aircraft is takeoff and landing. Crahes on takeoff continue to kill skydivers.

Do your part for global warming: ban beans and hold all popcorn farts.

[rickjump1 0]

Yes, I know how to spell crash.

Do your part for global warming: ban beans and hold all popcorn farts.

[Praetorian 1]

All this imput is great, but when you make comments add justification please, also saying things like "economical or fast climbing" are useless if they don't have some physical reasoning behind them (I really like the comments about wing shape between the caravan and otter) Tricycle gear (I'm guessing for insurance reasons and /pilot visability?) and while I like the Idea of viedo gear/gps screen in the back and then neon belts deisgned to fit through gear, these have very little to do with the design of the plane. (oh thanks by the way all this has been great so far)

Good Judgment comes from experience...a lot of experience comes from bad
judgment.

[riggerrob 558]

All the suggestions about uprated Twin Otters or shrunken C-119s are amusing, however, they ignore all the mid-sized DZs that are too busy for Cessnas (4-6 seats), but cannot fill Twin Otters (19-22 seats). Even my boss, who has flown Beech 18s (12-14 seats) and now a King Air B90 (14 seats) admits that ten seats would be a better size for Pitt Meadows.
Let's return to Nightjumpers' suggestion about 10-12 seats being the ideal size.
And to keep costs in line, let's stick with a single engine and fixed tricycle gear.

The inflight door/ramp should be electrically operated from the pilot's set, with emergency switches - in a guarded recess - beside the exit lights.

[calphoto 0]

Basically what we want is a 182 on steroids, but something smaller and less expensive than a Caravan.
1. High wing for many reasons including short/soft/gravelly runways. This wing should be a big fat Otter-type wing with stall fences and vortex generators for short-field/high gross weight operations. Also room for lots of fuel for the occaisional ferry flight.
2. Ten place for two four-ways plus videos each/eightway plus two videos/two tandems with one video plus a four-way and video, etc.
3. Piston engine for lower acquisition cost - make it the water-cooled Voyager engine, which eliminates shock cooling in the decent, plus turbo-super charging for continuous climb power to altitude.
4. Ramp tail end a'la C130. High drag, but most of the plane's life will be spent climbing at slow airspeeds, where drag is not that much of a factor, or in the decent where drag is an advantage. Ramp exits - WOO HOO!
5. Large exit door on the side above the struts for door exits. The C130 does this also. If we are going ultimate, a large door on the left side like the Otter, and a small door on the right to use the strut like the C182.
6. Two seats up front in addition to the 10 jumpers. Left seat of course is for the Pilot, or as so many jumpers lovingly call him/her, the "elevator operator". Right seat is for training jump pilots, flying observers (who pay more per ride than up-jumpers) or an ELEVENTH jumper. Yee HAH!
7. Speedbrakes. Let me emphasize this - SPEEDBRAKES!!! On a piston-engine drop ship, they can cut two to three minutes off each run. See the STC on speedbrakes on C182's.
8. Large windows in the passenger compartment. Make the ride up a bit more enjoyable and less claustraphobic for new students.
Now, having all of these features, the perfect drop ship has the capability for an alternate life when it is not flying jumpers. Any businessman knows that an airplane sitting on the ground is an expensive paperweight.
1. With the ramp and large open volume, we can do cargo. BIG bulky cargo. Pallets. Containers.
Cars. Night cargo, when all good jumpers are sleeping.
2. Big windows designed into the plane, as opposed to added on like the observation windows added expensively onto the Otter - sightseeing, or GREAT benefits to using the plane for short-haul commuter operations in scenic areas.
3. Military for all of the above reasons. (Though if it is not a turbine, most military operations will not look at it...)
During thousands of jump runs, a pilot dreams...

Hartwood Paracenter - The closest DZ to DC!

[pilotdave 0]

I wouldn't go with a single piston engine on a plane that size. Jet fuel is cheaper and turboprops are much more reliable. Avgas is easier to get at most airports now, but it'll be phased out over the next 20 years anyway. If the new diesels "take off," jet fuel will become common.

Dave

[rickjump1 0]

The turbine engine is the future, but it will take the Japanese or European competition(like the Walter) to give us affordable engines for the smaller operator.

Do your part for global warming: ban beans and hold all popcorn farts.

[riggerrob 558]

1. High wing for many reasons including short/soft/gravelly runways. This wing should be a big fat Otter-type wing with stall fences and vortex generators for short-field/high gross weight operations. Also room for lots of fuel for the occaisional ferry flight.

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Stall fences yes, because they improve aileron control near the stall.
No vortex generators. Aeronautical engineers consider VGs "nerdy" fixes to poorly-designed airfoils. Hire someone like Harry Riblet to design airfoil sections and you won't need those silly VGs.

Two separate fuel tanks are important. The first fuel tank would only old a couple of hours worth ... in other words a typical jump plane fuel load, like the nacelle tanks on King Airs. A second fuel cap would allow you to fill the ferry tank. Paint lots of data around the two different fuel caps.
While you are designing fuel tanks, rivet dip sticks to the inside of fuel caps and install ACCURATE fuel gauges.

[chopchop 0]

hmmm... lessee.... what seems to be missing in the Byron King Air... AH! Got it!

A full bar with cocktail waitresses in skimpy little outfits.. that would be great!

Oh, yeah.. and space for them to walk around and serve us.

chopchop
gotta go... Plaything needs a spanking..

Lotsa Pictures

[calphoto 0]

Actually stall fences are used to prevent span-wise loss of lift (departure of the boundary layer) ACROSS the wing. Some early fighters, usually Russian, had as many as three per wing.
Even the best airfoil can be helped by VG's, so long as you accept the tradeoff of low-speed control vs high speed drag. Look at the Twin-Otter tail and you will find LOTS of VG's. It is more a matter of philosophy than anything else.
I like the idea of dip-sticks on the fuel caps. It would be a great backup for the digital mass-sensing fuel level sensors, like the jets use.
The argument of piston vs turbine gets down to cost. Some of the new planes are being certified for both piston and turbine - Malibu Mirage vs the Meridian. With new Cessna 206's going for in excess of $400K, a $250k turbine installation might make purchasing a new aircraft prohibitive. You can get Twin Otters for less than a new 206.
Design/certify the airframe to be compatible with several options - piston, diesel, jetprop.

Hartwood Paracenter - The closest DZ to DC!

[Kid_Icarus 0]

Quote

bombbay doors. ability to strap several people under the wings. laser guided spotting helmets with night vision. dont forget the drink holders!

My stomache hurts form laughing so hard!!!

________________________________________
"What What.....

[riggerrob 558]

The biggest limitation with piston engines is horsepower. The normally-aspirated 6-cylinder Continental and Lycoming engines currently powering jump planes are limited to about 300 horsepower, which means that you are limited to 6 seats if you want a reasonable rate of climb.

Yes, I know it is possible to squeeze more horsepower out of those engines with turbo-charging, but the problem with turbo-charging is that even with a very smooth hand on the throttle, they still have shorter TBOs.
This forces you to choose between a dragster and a school bus.
Yes I have jumped out of an 8-seater Gippsland GA-8 Airvan, but with only 300 horsepower, it does not climb fast enough for me to make a living. Gippsland is mumbling about an Airvan version with a small turbine, but Gippsland has to sell a few hundred piston-pounders before they can pay off development costs. Don't hold your breath.

Both Continental (Tiara) and Lycoming (IO-720 retrofitted to Excalibur Queen Air) have tried building flat eight engines - in the 400 horsepower range - but quit a long time ago.
May be the solution is convincing Continental to string together eight liquid-cooled Voyager cylinders to built an engine in the 400 horsepower range.
I suspect that this will not happen until several Navajo fleet owners believe that the conversion will save them money.
By the same token, if we want 300 to 400 horsepower deisels, we will have to wait until serious numbers of Navajo operators believe the conversion will save them money.
The bottom line is that if you want to haul more than 6 jumpers, you need 400 or 500 horsepower and neither Continental or Lycoming has succeeded in building a reliable piston engine engine in that horsepower range.