Video shot by Air-Clips.com showing a glimpse of the P&W Canada 5 engined 747SP testbed. Also a favorite, taxing Nolinor B737-200 gravel runner (www.fliegerfaust.com) さらに...
That is how they test the smaller fans. I believe GE has done one as well, an old B742 if I recall. Add one small nacelle, and all of the appropriate instrumentation, and hey-presto, an instant moving test stand.
We did things similar when I worked at Cessna in the experimental flight dept. During Citation Mustang testing, we had the little PW615 engines on the RH pylon of our CJ2. Looked funny, but worked for testing. PW on one side, Williams on the other.
Both GE and Rolls-Royce use the B747..RR just acquired a second unit at the end of 2019, a B744 ex Quantas unit. It should be testbed ready end of 2021. I believe it is because the way the wing on the port side is configured structurally. The oddest testbed I have seen thou, was P&W Canada's B720 "Red" The nose was elongated, Pitot tubes repositioned then a PW150 turboprop mounted on the nose to test
For a second there i thought you were rapidwolve you both have the same wolf pic lol. The left wing on the 747 has the capablilites to haul a 5th spare engine. I believe its beefed up to handle that weight of another engine and thats why they use the 747 because I dont think I have seen any test engines outside of the number 2 spot.
I am..changed my name due to flack..yes..structural supports allow for a 5th pylon OR larger engine in place of #2. Take a look at the article here..P&W Canada are not using #2 spot, and if you get a chance, check out P&W Canada's, now retired, B720
I have to assume that P&W did their homework on this, but can someone explain to me how this is the optimum location for the "5th engine"? I understand that this is an engine test bed, but that location seems unnecessarily inaccessible.
Rolls Royce has a 747 that is just like this, though the 5th engine is on the other side. GE puts a third engine under the wing on their 747. Like Scott said this puts the engine in clean air, shows the performance on a wing with only one engine, and can be structurally secured in the cabin.
My guess would be that it's the best place to put it because it is out of the way of any disturbances. Forward and high enough that it's riding in clean air.
Actually that extra engine is what they use when the upper deck separates from the balance of the aircraft like on Star Trek. Of course its only used in emergencies like a Romulan attack.