Couple of interview technical questions
Join Date: Jun 2002
Location: Wor Yerm
Age: 68
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
I think the reason the F27 Mk50 ended up with high wing was to stop the propellers banging on the ground when the aircraft was in it's Mk1 state (well, it was either that or a ten foot undercarriage and ladders to get in and out). When the F27 was designed (rumour has it for radial piston engines) the props where so large that the wing had to be on top of the fuselage. Later on, when Fokker "updated" the F27 (to the Mk50 - aka F50), the only person building engines of the right size was Pratt and Whitney with the PW127 and they came with in a package with six bladed props.
But the best reasons for high wings are for ground handling. No special equipment required (except for ground coolers on hot days). It also makes it more difficult for those on the ground to bump into things.
And six bladed props - they are pretty quiet and can still absorb the power put out by the engine. In CLB and CRZ I think they do 800 RPM.
But when you fly a F50, you can help but ask - where does all this power go? The ATR 72 has less, carries more, goes faster and burns less.
But the best reasons for high wings are for ground handling. No special equipment required (except for ground coolers on hot days). It also makes it more difficult for those on the ground to bump into things.
And six bladed props - they are pretty quiet and can still absorb the power put out by the engine. In CLB and CRZ I think they do 800 RPM.
But when you fly a F50, you can help but ask - where does all this power go? The ATR 72 has less, carries more, goes faster and burns less.
With regards lift, high wing aircraft are able to produce some lift from the bump on the top of the fuselage at the wing root
- Duckbelly! Since when was the 146 above 60t? And it wasn't that long ago! Besides, as the 146 had a high wing, you should be an expert on it
Thread Starter
Join Date: Oct 2002
Location: Perth, Oz
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
Hmmmm. When was the last time we talked?? Been on the 73 for a few years now. Does that qualify??!!
I auto dumped the 146 the day I started my 73 endorsement!!
Send me a pm with contact details. Seeya!
I auto dumped the 146 the day I started my 73 endorsement!!
Send me a pm with contact details. Seeya!
WRT the F27 it was originally designed to replace the DC 3, the use of the high wing allowed a lower fuselage "lip height allowing rapid on/offload w/o extra ground equipment. if you look at the HS748 you can see that it would have been possible to go low wing, with the same engines. however forklifts are necessary to load/unload. one of the reasons for the ATR's higher speeds are a higher wing loading, and a smaller fuselage, and more streamlined front end. The F27 vs the HS748 F27 is 10-15 kts faster, but the 748 will go into a 3000' strip w/ a full load. having flown both of them I prefer the 748 for it's human factors/systems. though I appreciated the "drag brakes" on the Fairchild version. Too bad they hadn't collaborated as a true high wing Hawker would still be in production with the Pratts and the ATR wouldn't have seen the light of day. Also the Darts if I remember correctly had a 10-1 reduction ratio and would have a prop speed of 1400-1500 rpm
