Delanne Tandem Wing Project

[synjin]

So, I was looking to make a tandem wing airplane and found a trail of information leading to Maurice Delanne who designed the Arsenal-Delanne 10-C2...which led to...well, you know, internet rabbit holes.

Anyway, I set out to build a Delanne tandem wing-esque plane. Started with the wing from the Bloody P-40 and designed around that (it's an easy to build wing and a solid flier). Mk.I glide tested well, but was crazy out of control when powered. I had calculated the CG as a canard, so the CG was off. Recalculated the CG, moved the power pod up to mid-fuselage, added bigger elevons, and it flew...okay-ish.
Mk.I.

More lessons about aerodynamics (lateral dihedral), increased wingspan, bigger motor and threw it up for a maiden today. I didn't even try to video it as the last version crashed repeatedly at first. This one jumped out of my hand and flew nicely on a 2S 900maH battery. The only thing I had to do was give it down elevator which means I'll have to take out the reflex I put on the elevons. Cruising, it ran at about 1/3 to 1/2 throttle.

Four batteries later (two 2S and two 3S 900mah), no crashes, five soft landings, and some flying wing-like acrobatics it came back without a scratch. There may be too much lateral dihedral (angle difference between the front and back wings). The front wing is 3 degrees up and the back wing is maybe 2-3 degrees down. Goofy looking aun to fly!

Wingspan: Front 25 inches, rear 19 inches
Length: 16.5 inches
Motor: 2208 2000Kv
Prop: 6x4x3
ESC: 20a
2 9g Servoes

She needs a cockpit, paint...and maybe French WWII markings.

Mk.III is cut out and ready to put together. It has a longer fuselage. I'll pull the electronics out of Mk.I to put into Mk.III. I still have to figure out a good landing gear arrangement.

I will post plans when I get the rear wing slot the right shape and angled correctly.

You can see the hole for an aileron servo that I didn't put in. I may still add that.

 

[Yayat]

interesting. May I ask why you need two wings (tandem wings) what is the purpose of this setup?

 

[synjin]

Here is an explanation http://www.nestofdragons.net/weird-airplanes/tandemwings/maurice-delanne-duo-mono/

Delanne was trying to make cheap, stable, easily flown aircraft that were forgiving (this was in the 1930's).

What I found today was that I had a hard time get this plane to stall. It mainly mushed out and sank instead of any kind of dramatic drop. It flies slow. I had about a 5mph wind today and just about hung the plane over head at 1/4-1/3 throttle. 3/4s throttle and the plane blasted off, again much like a flying wing. The soft landings really were due to the plane not stalling out and just mushing in, and I had positive control all the way down.

Why did I build it? Because, I thought it was an interesting historical design concept. The model really does do most of what Delanne was trying for.

Originally, I wanted to build this fantasy aircraft.

I may yet build and try to fly this. However, this plane has the front and rear wings on the same plane, which can cause tumbled air for the rear wing. The Delanne tandem configuration avoids that and is supposed to give greater elevon authority.

 

[synjin]

Hope to test Mk.III later today.

 

[Monte.C]

So, I was looking to make a tandem wing airplane and found a trail of information leading to Maurice Delanne who designed the Arsenal-Delanne 10-C2...which led to...well, you know, internet rabbit holes.

Anyway, I set out to build a Delanne tandem wing-esque plane. Started with the wing from the Bloody P-40 and designed around that (it's an easy to build wing and a solid flier). Mk.I glide tested well, but was crazy out of control when powered. I had calculated the CG as a canard, so the CG was off. Recalculated the CG, moved the power pod up to mid-fuselage, added bigger elevons, and it flew...okay-ish.
View attachment 176214 Mk.I.

More lessons about aerodynamics (lateral dihedral), increased wingspan, bigger motor and threw it up for a maiden today. I didn't even try to video it as the last version crashed repeatedly at first. This one jumped out of my hand and flew nicely on a 2S 900maH battery. The only thing I had to do was give it down elevator which means I'll have to take out the reflex I put on the elevons. Cruising, it ran at about 1/3 to 1/2 throttle.

Four batteries later (two 2S and two 3S 900mah), no crashes, five soft landings, and some flying wing-like acrobatics it came back without a scratch. There may be too much lateral dihedral (angle difference between the front and back wings). The front wing is 3 degrees up and the back wing is maybe 2-3 degrees down. Goofy looking aun to fly!

Wingspan: Front 25 inches, rear 19 inches
Length: 16.5 inches
Motor: 2208 2000Kv
Prop: 6x4x3
ESC: 20a
2 9g Servoes

She needs a cockpit, paint...and maybe French WWII markings.

Mk.III is cut out and ready to put together. It has a longer fuselage. I'll pull the electronics out of Mk.I to put into Mk.III. I still have to figure out a good landing gear arrangement.

I will post plans when I get the rear wing slot the right shape and angled correctly.

View attachment 176211
You can see the hole for an aileron servo that I didn't put in. I may still add that.
View attachment 176212 View attachment 176213

I think that's an awesome choice. Love these "different" designs.

 

[synjin]

Mk.III is a winner!

Front wing angle of incident is 3 degrees, rear wing 0 degrees. I used the motor and ESC from Mk.II because I was lazy and didn’t want to solder a new setup, and I added a servo to the wing for ailerons. I added a canopy...just so it looked like the drawings of the Delanne DL-160.

Looks good to me. I stretched the fuselage an inch and a half. Same wings as Mk.II, however I used the front wing cutout for the ailerons from the Bloody P-40 plans and the wing is thinner as I used foam board (as opposed to 1/4” blue foam) and a simple 3/16” spar. Standard FT throws on the ailerons and elevons with dual rates, and I started on low rates (never did have to go to high rates). First flight, 2S 900maH.

I threw it up wondering whether it was going to fly or die. It took off straight and stable, and climbed out was good. It has less torque roll than Mk.II. Great power, even on 2S, though I wonder whether a 2208 2000Kv motor is over-powered. It goes fast, it goes slow, and it doesn’t stall or drop a tip. With no power it just mushes down on full up elevator. The addition of the ailerons makes the rolls VERY snappy. Mk.II was a little sluggish as far as roll rate.

With dihedral only on the rear wing, a little bit of roll puts it into a gentle turn. Control is good even at low speed right down to landing. If I understand the principle of the configuration, the rear wing is in a delayed stall, so it should have positive control as long as it has airspeed.

Still need to work on trim. It climbs some after coming out of a turn, and it still noses up when punching the throttle. Now I just have to work out landing gear and clean up the plans

 

[Monte.C]

Mk.III is a winner!
View attachment 176807
Front wing angle of incident is 3 degrees, rear wing 0 degrees. I used the motor and ESC from Mk.II because I was lazy and didn’t want to solder a new setup, and I added a servo to the wing for ailerons. I added a canopy...just so it looked like the drawings of the Delanne DL-160.
View attachment 176806
Looks good to me. I stretched the fuselage an inch and a half. Same wings as Mk.II, however I used the front wing cutout for the ailerons from the Bloody P-40 plans and the wing is thinner as I used foam board (as opposed to 1/4” blue foam) and a simple 3/16” spar. Standard FT throws on the ailerons and elevons with dual rates, and I started on low rates (never did have to go to high rates). First flight, 2S 900maH.

I threw it up wondering whether it was going to fly or die. It took off straight and stable, and climbed out was good. It has less torque roll than Mk.II. Great power, even on 2S, though I wonder whether a 2208 2000Kv motor is over-powered. It goes fast, it goes slow, and it doesn’t stall or drop a tip. With no power it just mushes down on full up elevator. The addition of the ailerons makes the rolls VERY snappy. Mk.II was a little sluggish as far as roll rate.

With dihedral only on the rear wing, a little bit of roll puts it into a gentle turn. Control is good even at low speed right down to landing. If I understand the principle of the configuration, the rear wing is in a delayed stall, so it should have positive control as long as it has airspeed.

Still need to work on trim. It climbs some after coming out of a turn, and it still noses up when punching the throttle. Now I just have to work out landing gear and clean up the plans

Killer. That looks really good. Glad it flies good too.

 

[leaded50]

nice to see @synjin , this thread i havent seen, but you got some relevant experinece with two-wings here, that also are recognized in early testreports in aviation. Im building the 20-T model (master-style) at moment.

 

[Monte.C]

Would you guys please stop following me??! As soon as I got this tandem wing on the drafting table, YOU guys came into the radar.
Funny how it happens that way!

 

[leaded50]

what?? its you who are slow.... Ha,ha

 

[Monte.C]

what?? its you who are slow.... Ha,ha

Oh no... I guess you're right.

 

[Monte.C]

Mk.III is a winner!
View attachment 176807
Front wing angle of incident is 3 degrees, rear wing 0 degrees. I used the motor and ESC from Mk.II because I was lazy and didn’t want to solder a new setup, and I added a servo to the wing for ailerons. I added a canopy...just so it looked like the drawings of the Delanne DL-160.
View attachment 176806
Looks good to me. I stretched the fuselage an inch and a half. Same wings as Mk.II, however I used the front wing cutout for the ailerons from the Bloody P-40 plans and the wing is thinner as I used foam board (as opposed to 1/4” blue foam) and a simple 3/16” spar. Standard FT throws on the ailerons and elevons with dual rates, and I started on low rates (never did have to go to high rates). First flight, 2S 900maH.

I threw it up wondering whether it was going to fly or die. It took off straight and stable, and climbed out was good. It has less torque roll than Mk.II. Great power, even on 2S, though I wonder whether a 2208 2000Kv motor is over-powered. It goes fast, it goes slow, and it doesn’t stall or drop a tip. With no power it just mushes down on full up elevator. The addition of the ailerons makes the rolls VERY snappy. Mk.II was a little sluggish as far as roll rate.

With dihedral only on the rear wing, a little bit of roll puts it into a gentle turn. Control is good even at low speed right down to landing. If I understand the principle of the configuration, the rear wing is in a delayed stall, so it should have positive control as long as it has airspeed.

Still need to work on trim. It climbs some after coming out of a turn, and it still noses up when punching the throttle. Now I just have to work out landing gear and clean up the plans

Question for you. Something that I still can't wrap my head around.
Are you able to clearly describe why 3 degrees incidence (or any incidence) is preferred with this build or a similar plane?
I get it about all the basics, CG and stuff, but this one's tough. There are all different conditions - fast speed, full throttle, gentle glide - I have a vague idea that if you trim the wings that way for a glide, you'd naturally get that nose up condition as you lay on the throttle.

I found a lot of old vintage plans with a trim angle in the wing, but then I'm thinking they didn't have any throttle control, so it was all in then glide home. ??

 

[leaded50]

on my Payen, i found that with 0 incident in rear wing, a couple degrees at front wing, made it glide a lot better.

 

[Monte.C]

on my Payen, i found that with 0 incident in rear wing, a couple degrees at front wing, made it glide a lot better.

Nice. But did it nose up with a burst of throttle? That's what I'm not sure about. Glide vs full power are different conditions.

 

[synjin]

Question for you. Something that I still can't wrap my head around.
Are you able to clearly describe why 3 degrees incidence (or any incidence) is preferred with this build or a similar plane?
I get it about all the basics, CG and stuff, but this one's tough. There are all different conditions - fast speed, full throttle, gentle glide - I have a vague idea that if you trim the wings that way for a glide, you'd naturally get that nose up condition as you lay on the throttle.

I found a lot of old vintage plans with a trim angle in the wing, but then I'm thinking they didn't have any throttle control, so it was all in then glide home. ??

I put in the angle of incidence because of the Fokker D-VII I built. The plans called for no angle of incidence. And while flying it I noticed that it flies level in a nose up attitude. After doing a little research I found that this is to be expected with an aircraft with no angle of incidence. The relationship between the angle of incidence of the front wing and that of the rear wing is referred to as lateral dihedral. I found this article helpful https://rcplanes.online/index5.htm.

I chose 3° because it looked about right. It’s close to what you see in the Mighty Mini Scout (which is a favorite of mine), so I started there. I’m sure there’s a way to figure out the optimal angle, I just don’t know how to do that. Before I change anything else, I’ll try resetting the reflex on the elevons to a little bit more negative than what they are now. At this point I’ve trimmed them all the way down, so I’ll have to adjust them and re-trim the aircraft.

With the current set up the fuselage looks level when I do low flybys. I think it’s pretty close to being correct. I just have to figure out a way to get the rear wing into the fuselage slot in an easy and consistent way when building. I think if the rear wing isn’t at 0° angle of incidence it causes the whole aircraft to want to nose up or do loops.

 

[Monte.C]

I put in the angle of incidence because of the Fokker D-VII I built. The plans called for no angle of incidence. And while flying it I noticed that it flies level in a nose up attitude. After doing a little research I found that this is to be expected with an aircraft with no angle of incidence. The relationship between the angle of incidence of the front wing and that of the rear wing is referred to as lateral dihedral. I found this article helpful https://rcplanes.online/index5.htm.

I chose 3° because it looked about right. It’s close to what you see in the Mighty Mini Scout (which is a favorite of mine), so I started there. I’m sure there’s a way to figure out the optimal angle, I just don’t know how to do that. Before I change anything else, I’ll try resetting the reflex on the elevons to a little bit more negative than what they are now. At this point I’ve trimmed them all the way down, so I’ll have to adjust them and re-trim the aircraft.

With the current set up the fuselage looks level when I do low flybys. I think it’s pretty close to being correct. I just have to figure out a way to get the rear wing into the fuselage slot in an easy and consistent way when building. I think if the rear wing isn’t at 0° angle of incidence it causes the whole aircraft to want to nose up or do loops.

Choosing the angle because it looks about right - that's how I decide the angles on my power pods!

Hey that makes a lot of sense. Especially with flat wings - like with no real airfoil - and low speeds, they do need to fly with up incidence. So you're programing the incidence into the wing. It still bothers me that it seems like at significantly greater speeds it would amplify the effect and want to make it pitch up... Not sure. Maybe it's designing by educated guess and past experience, and others' findings I suppose.

I don't like when I can't disassemble an issue and understand it piece by piece. Ugh! Thanks for your explanation. And you've got a seriously cool plane there. It looks much better in the flesh than it does on paper.

 

[leaded50]

here, more to learn on Dual-wing plane theories/science.
https://docplayer.net/58756434-The-tandem-wing-theory-experiments-and-practical-realisations.html

 

[Monte.C]

here, more to learn on Dual-wing plane theories.
https://docplayer.net/58756434-The-tandem-wing-theory-experiments-and-practical-realisations.html

Thank you!

 

[leaded50]

here is a design project of later dates from England, ... still the dual-wing...

 

[leaded50]

Of so-called Nenadovich biplane or tandem wing configuration, the tandem-mounted wings providing a continuous slot effect and offering exceptional center of gravity range.

Relative angle of attack between the upstream and downstream airfoils (δ = α w α p ), where each angle of attack is taken with respect to the free stream. The decalage is therefore positive if the forewing incidence is greater than that of the rearwing or negative if the converse is true.

Positive decalage results in greater lift from the upper wing than the lower wing, the difference increasing with the amount of decalage (angle difference between the upper and lower wings chords)
In a survey of representative biplanes, real-life design decalage is typically zero, with both wings having equal incidence. A notable exception is the Stearman PT-17, which has 4° of incidence in the lower wing, and 3° in the upper wing. Considered from an aerodynamic perspective, it is desirable to have the forward-most wing stall first, which will induce a pitch-down moment, aiding in stall recovery. Biplane designers may use incidence to control stalling behavior, but may also use airfoil selection or other means to accomplish correct behavior.

For me, is seems the older dual-wing configurations is more of "STOL" capacity than speed.. even if such configuration give possibility for thinner airfoils, and less wingspan and smaller plane (aka speed and then quicker maneuverability eg.). And that the CG point get easier eg. by loads, so isnt as necessary to place it at actual point.
By some theories though, its mentioned that the room between for & aft "wings" can help less drag, and in subsonic we can today see lot of plane designs with a tandem systems, even if is just canards (who also is a tandem-wing versions)