Otter..whats the story..

[Tupperware Pilot]

...here!
http://farm9.staticflickr.com/8259/8671689825_ca29302ae1_m.jpg (http://www.flickr.com/photos/kemon01/8671689825/) What is going on here? (http://www.flickr.com/photos/kemon01/8671689825/) by Kemon01 (http://www.flickr.com/people/kemon01/), on Flickr

[Jhieminga]

Short take-off and landing Otter, the final version in this development was fitted with a sturdy four-wheel undercarriage, a larger vertical tail unit, Bat-wing flaps (as seen in the shot above) and a turbine engine in the fuselage with movable nozzles on the fuselage sides which deflected the exhaust forward and down.

Have a look at this book for more about it: http://www.amazon.co.uk/gp/product/1857800869/ref=as_li_ss_tl?ie=UTF8&camp=1634&creative=19450&creativeASIN=1857800869&linkCode=as2&tag=alittlevc10de-21

[Rosevidney1]

It sports a more angular rudder but look at those enormous flaps! :confused:

[Jhieminga]

It's been a while since I read the book but I managed to find it pretty quickly, apologies for a sloppy scanning job. Otters 3674 and 3682 were used to develop a shorter landing Otter with the aim of crossing a 50 foot obstacle and landing in less than 500 feet. They reached a figure of 362 feet after the obstacle with the phase two aircraft. In the end severe structural problems due to sonic fatigue inside the fin ended the program and the aircraft was scrapped.

http://www.vc10.net/div/Otter_1.jpg

Ground effect testing on Otter 3674 in 1957. Tufting installed to show airflow, fully deployed batwing flaps and engine running to blow flight surfaces.

http://www.vc10.net/div/Otter_2.jpg

Phase one Otter 3682 with bat flaps operated by external actuators low on the fuselage, drooped leading edge and new tail and landing gear, summer 1959.

http://www.vc10.net/div/Otter_3.jpg

Phase two Otter 3682 on final approach with J-85 modulated valves supplying reverse thrust through forward slot, enabling the X-Otter to descend nearly vertically.

http://www.vc10.net/div/Otter_4.jpg

Officially this was the DRB-DHC STOL Research aircraft twin.
In its phase three configuration the Otter sported the reverse thrust J-85 (note intake between wing trailing edges) and twin PT-6 turboprops replacing the nose-mounted R-1340 radial piston engine, seen here in 1964.

(All photos and info from the book I linked to in a previous post.)

[Tupperware Pilot]

Thanks for the details...i knew someone would know...
Very helpfully..

[A30yoyo]

Fascinating , but why when helicopters were proven and successful?

[Wizofoz]

Have Helicopters EVER been proven and successful?

But, seriously, a fixed wing aircraft will always be more economical than a chopper- you only use a Helicopter when the task simply CANNOT be achieved by a fixed wing.

[Rosevidney1]

I'm sure it was an experiment worth pursuing at the time as helicopters in those days were short on range and payload.

[Noah Zark.]

It looks as though it was designed by the same bloke who designed the Rutland Reindeer!



http://www.impdb.org/images/thumb/3/39/NHITS_Halifax_2.jpg/500px-NHITS_Halifax_2.jpg

[Agaricus bisporus]

What's the story on that bizarre undercarriage?

[DaveReidUK]

What's the story on that bizarre undercarriage? I think the clue is in the caption to the first photo in post #4:

Ground effect testing on Otter 3674 in 1957. Tufting installed to show airflow, fully deployed batwing flaps and engine running to blow flight surfaces.The purpose of the rig is presumably to get the desired clearance between the wing and the ground. It's not clear whether the rig is intended to be towed, or whether it's just the prop that's providing the airflow to energise the lifting surfaces.

Either way, it clearly isn't expected to leave the ground trailing all that ironmongery. :O

[A30yoyo]

I suppose DHC were taking STOL as far as they could get it funded....by the time the Twin Otter came along I think the S-61 was in service . DHC presumably incorporated lessons from their STOL experiments in the Dash-7
http://i809.photobucket.com/albums/zz20/A30yoyo/132001DHC-7a850_zps56b2d58f.jpg (http://s809.photobucket.com/user/A30yoyo/media/132001DHC-7a850_zps56b2d58f.jpg.html)

[Jhieminga]

What's the story on that bizarre undercarriage?
If you mean the clunky bits in photos 2, 3 and 4, it was the easiest way to get a tricycle (actually quadricycle) gear, eliminating the unstable tendencies of the original Otter tailwheel layout. Also it was beefed up considerably to withstand high sink rates on touchdown, just look at the massive forged trailing links on those maingears. They were doing 18 degree approaches at one point, a slightly misjudged touchdown might have ruined their day with the original gear.

It's not clear whether the rig is intended to be towed, or whether it's just the prop that's providing the airflow to energise the lifting surfaces.
There is a cable running from the truck in front to the rig in the first photo I posted, but the scan isn't clear enough to show it well. I recall from the story that they did tow it up and down the runway. It was basically a big open windtunnel test.

[India Four Two]

The data obtained during testing of the DRB-DHC STOL Research aircraft twin (1964 photo in post 4) was used in the design of the Twin Otter, which was launched in 1964. I'm glad DHC got rid of that ugly fin, though!