What's the udes of Triplanes

[Fred van Woerkom]

I wonder if anyone can tell me why

1. triplanes were used .e.g. by von Richthofen

2. they went out of use shortly after?

Cheers,

Fred van Woerkom

[aleyoop]

The 3 wings gave the aircraft a large wing surface area so greater lift and manoeuvrability but considerable drag so reduced speed. The concept of a nippy if slow scout had limited life and fell out of favour against less manoeuvrable but faster aircraft. For a better discussion, have a look at

http://www.theaerodrome.com/forum/index.ph...45&hl=triplanes

[Fred van Woerkom]

Thanks, Vin.

I am a complete igoramus as regards aviation, but most of your answer seems what I have always thought. The problem is : how could a Triplane combine manoeuvrability with reduced speed. Manoeuvrability in what way? Certain rolls or loops?

If a triplane has more lift, is it more difficult for the pilot to dive?

I am looking forward to your answer.

Cheers,

Fred

[aleyoop]

Reduced speed means a tighter turning circle so if it is being pursued, it can turn inside the turn of its pursuer and become the pursuer. Greater lift means that it can maintain altitude or regain altitude at the end of a manoeuvre. It had a lower stall speed so that it could continue to manoeuvre when biplanes would stall because of loss of energy exerted in a series of manoeuvres. The Dr 1 was a light weight interceptor type with limited endurance. Its role was defensive. It met the enemy which came to it, engaged in dogfighting within a limited area and then retired. Dog fighting was accompanied by loss of altitude which is where the triplane’s advantage was demonstrated. It was unsuited to the role of an attack aircraft, had too limited air time and its air speed was too low to venture across the lines in an attacking role.

[Guest Pete Wood]

Thanks for that, Vin. I've certainly learnt a bit about Triplanes.

So did the Fokker DR1 ever come up against the Sopwith Tripe - and what were their relative strengths and weaknesses....??

[aleyoop]

As far as I have read, no, the Sopwith Triplane never encountered the Dr 1 in combat. The relative merits of the two are discussed in the link I posted above.

Who would believe it, me the expert on triplanes !! Everything I know has been picked up over the years on forums like this one and, particularly, theaerodrome forum.

Vin

[Howard]

If a triplane has more lift, is it more difficult for the pilot to dive?

If an aircraft dives it gains speed. Every aircraft has a maximum speed above which there is a chance of instability, flutter or structural failure.

The issue of "high lift" is a little misleading. The lift an aircraft needs in level flight is about equal to its weight. If a "low lift" aircraft and a "high lift" aircraft of the same weight are in level flight, the low lift one needs more speed to generate the same lift. I fly an AA1, about the same weight as a C152. The AA1 stalls at 57 knots, the C152 stalls at least 10 knots slower, but it can only cruise at 85 knots, whereas I do 105 knots on the same engine and power setting. In this sense, the C152 is "high lift" but you pay the price, high lift=high drag=lower maximum level speed.

You can fly tighter loops in a "high lift" aircraft because you are going slower. In a loop, the harder you pull on the pole the tighter the loop until something breaks, the aircraft, the lift or you! You can stall an aircraft at high speed just the same as at low speed, pull too hard and it bites. A 4G loop in a triplane would be tiny in diameter, a 4G loop in a Tornado would need a lot of sky as it is much faster.

To dive without gaining too much speed, one can side slip, full left aileron plus full right rudder does the trick in my aircraft, it goes down like a lead balloon at 80 knots provided I do not let the nose go down. It also gives you a splendid view down the side of the aircraft. In some types, even modern ones like the Pitts Special, one has to side slip to landing or the runway is not visible.

I suspect Great War pilots were very good at side slipping, even if only to give a good forward view.

Howard