SAAB VTOL project

[Pellson]

The X-32 isn't a four-poster lift design like the Harrier, it has a 2-D rotating nozzle like the F-35 and the Yak-141. The SAAB delta design wouldn't have worked because of the standard Pegasus four nozzle configuration. The biggest problem being trying to push all of that flat area straight-up, there's a reason the Harrier had small wings, the trapped exhaust efflux would cause all kinds of problems.

That's about where I'm getting to as well.
However, on second thought, the wing area as such is not that much bigger than on the Harrier. Its just distributed differently, and, I believe, poses a bigger hinder for any venturi effect of the nozzles whereas the Harrier's more narrowchorded wing will impede less.
Now - build one anyway, neglecting physics, or changing to something that might have worked? That's the question..

[Wardukw]

The X-32 isn't a four-poster lift design like the Harrier, it has a 2-D rotating nozzle like the F-35 and the Yak-141. The SAAB delta design wouldn't have worked because of the standard Pegasus four nozzle configuration. The biggest problem being trying to push all of that flat area straight-up, there's a reason the Harrier had small wings, the trapped exhaust efflux would cause all kinds of problems.

That's about where I'm getting to as well.
Now - build one anyway, neglecting physics, or changing to something that might have worked? That's the question..

Build it as a prototype proof of concept model so the dudes with the money can see what it would look like in 1/1 scale   
That's been done with real aircraft hundreds of times .

[Pellson]

Nah. Half the fun is in the backstory describing the service of the type.. 

[Wardukw]

Nah. Half the fun is in the backstory describing the service of the type.. 

A glutton for punishment I take it   
Then please my good Sir proceed   

[Dizzyfugu]

Having dug out an old Harrier corpse and a few wings, there's two ways of going about this. Either do a delta, and may the devil take the aerodynamics, or go with alternative and less "Camm-ish" wing/fin. Both ways have their benefits. While the delta might be more close to the RW project, the SAAB 29 Tunnan wings actually fit "bolt on. Now - isn't that a coincidence..?

I'll read up on actual Harrier GR.1/GR.3 operations before deciding, methinks. Were they really flown fully VTOL in the field, or was it more a matter of limiting runway demands rather than annulling them, i.e STOL?

Yes, they fit perfectly. And they look good. I have done so in the past, yet w/o visual evidence. 

[RAFF-35]

I started making one of these last year but the project got shelved. I need to re-start it though 

[jcf]

Maybe change the lift nozzle arrangement? Keep the Harrier type forward but install Yak-36 type
further aft and lower on the fuselage. It would mean a longer tailpipe assembly, but it would look
cool and maybe it would even improve the lift capability despite the delta wing. 

[Weaver]

The X-32 isn't a four-poster lift design like the Harrier, it has a 2-D rotating nozzle like the F-35 and the Yak-141. The SAAB delta design wouldn't have worked because of the standard Pegasus four nozzle configuration. The biggest problem being trying to push all of that flat area straight-up, there's a reason the Harrier had small wings, the trapped exhaust efflux would cause all kinds of problems.

The principle reason why the Harrier had small wings was to reduce 'dead' weight in the hover as much as possible. Given that Harriers ascend quite slowly in VTO, I doubt whether the air resistance of a bigger wing would have much effect: after all the AV-8B's wing is MUCH bigger than the AV-8A's.

Trapped exhaust efflux can be a blessing or a curse, depending on how intelligently you can exploit it. The AV-8B does a good job of this. The reason why it's inboard pylons are so deep is because in the hover, the flaps are dropped, creating a 3-sided box between the fuselage, the pylon and the flap, which increases lift when in ground effect. Likewise, it has a 4-sided box under the fuselage, formed by the gun pods and/or their strakes, the main gear door and a retractable air dam (the LID: Lift Improving Device) between the pods at the front. I don't see why, in principle, the SAAB design couldn't do similar things, and perhaps even get more lift boost due to the bigger wing area.

My main issue with the SAAB's wing planform is that 60-ish degree deltas are best suited to supersonic applications, but the Pegasus's low net exhaust velocity makes that impossible. In level flight, a Pegasus is more akin to a an airliner's high-bypass turbofan than a 'proper' fighter engine. That's why the P.1154's BS.100 engine used plenum-chamber (i.e. cold nozzle) burning instead of hot nozzle afterburning: the most critical thing to make it go faster was to raise the low exhaust velocity of the front nozzles.

The delta wing also puts outboard weapons stations a long way behind the CofG compared to the Harrier's wing, and CofG balance is especially critical for a VTOL design.

[Pellson]

Just a friendly reminder that I've started a proper build thread over >>HERE<<.