Delta photo plane design help

[Italian Flyer]

Hello to all the aerodynamics experts, I am scratch building a new camera plane and I would like it to be a delta, but with a higher aspect ratio than usual so , almost a plank with swept wings. This is the deal, I have already built a section of the fuselage... it is pretty much a tube cut out of blue foam, the diameter is 15 cm outside and 14 cm inside, it's been sheeted with 0.8mm balsa inside and outside, so now it's a neat looking tube balsa-foam-balsa sandwitch. This tube is 40 cm long. The camera will be mounted in the nose. I just can't decide at this point what type of wing planform and airfoil to use... The plane needs to be able to lift a 6 oz digital camera, and rarely a 11 oz digital camera. the batteries will be 8 cells 3000 nimh or some 8 cells kan 1050 in case the other pack is too heavy... and for motors, here's the problem... I want to use what I have at home... which is either a astro 020 brushless with 4.4/1 planetary gb, or I have several speed 400 6v motors, I guess I would need at least 3 or 4 in direct drive to lift this plane, also I have one gearbox 3.3/1 for speed 400, and also I have a Kyosho AP29L motor, which has a very high kv. I really don't want to buy other power systems as these are just sitting around... and collecting dust. The astro 020 will give about 48 oz thrust with a 12/8 apc slow flyer prop and draw about 16 amps.
What do you suggest to complete this plane? I want to have medium to high lift, slow stall speeds, and decent glide and wind penetration.
at first I wanted to use a eppler 423 high lift airfoil and a conventional configuration, then I though that I could save weight by doing away with the tail and just making it a flying wing with a very large pod.
Should I use an airfoil like the MH60, or maybe something with a reflex like the Phoenix airfoil, so I can do away with washout... I would not want a wingspan larger than 60 inches. I am also trying to determine the root chord and tip chord, washout degrees if needed, etc. I hope you can help me make up my mind about this. Thanks..

[vintage1]

I'd use 4x speed 40o 6v and more or less copy a Zagi or Picojet type wing. Its pretty thick sectioned.

[Sparky Paul]

Not enough power for the camera.
I put a 2 oz Aiptek in a Zagi, with a direct drive 400. It would barely climb, while the unballated plane would do quite well.
Look at what Tom Harper has done with deltas, and CenTexFlyer in their threads here.
For the modest power a 400 delivers, geared or direct, a conventional wing-tail plane will be a better choice.
Brushless motors will do better, in any event.

[Italian Flyer]

I'd use 4x speed 40o 6v and more or less copy a Zagi or Picojet type wing. Its pretty thick sectioned.

yup. I thought about it.. 4x speed 400 6v should give plenty of oomph, but I only have 2 ESC, the biggest one being a 35 amp esc by astro... and that is not BEC either, then I have a 25 amp esc with bec...

I though about using 2x speed 400, switching the ferrites with neodymium magnets... that should bring the kv down and up the torque... My guess is that I could use 10x4.7 apc slow flyer props at about a 12 amp draw and 6000 rpm. double stacking 20x4x2 mm magnets, so I would have 20x4x4 mm magnets times 6 on each side of the can, that should bring the magnets very close to the stator... and bring the efficiency way up.

is it feasable??

[Andy W]

Wings and Delta's typically don't have the stability and self-righting ability that make for good AP platforms. OK for close up work, but for altitude and distance, a high-wing trainer-style model is best.
..a

[Italian Flyer]

Andy, I thought about that, in fact, I am still not sure if I want to make a flying wing or not... what I can tell you is that I have very experienced thumbs, which should provide plenty of stability... I am not sure I want to fly a self-righting plane.. that's quite scary, I prefer to fly a plane that only does what I tell it to... I guess it's a matter of preference. If I were to build a high winger, as originally intended, I would definitely not use any dihedral...it's just the way I like to fly...
Now if I were to make it a high-wing conventional plane, what airfoil do you suggest?
E-203, e423, wortman fx series, sweep angle of the wing (degrees etc), wingspan.. root cord vs tip cord. This is the type of info I guess I need, so many possibilities, but what is the best one?

[Arthur P.]

A simple search for 'delta' in the Aerial Photography forum gets you these, among others:

http://www.rcgroups.com/forums/showthread.php?t=285405&highlight=delta+

http://www.rcgroups.com/forums/showthread.php?t=262629&highlight=delta+

http://www.rcgroups.com/forums/showthread.php?t=261740&highlight=delta+

http://www.rcgroups.com/forums/showthread.php?t=258407&highlight=delta+

http://www.rcgroups.com/forums/showthread.php?t=323919&highlight=delta+

http://www.rcgroups.com/forums/showthread.php?t=362703&highlight=delta+

[Andy W]

At 1500'-2000', a stable, self-righting airframe is my personal preference.. to each their own, however..
..a

[vintage1]

4x 6v speed 400 GEARED on 3s LIPO is within 35A draw. Efficient too.
Should heft around 6lb total more or less.

I would myself plump for the stable trainer style platform however.

[Italian Flyer]

I guess, making it a high wing platform, it's just got a better chance to work. Definitely the quad motor would be just way cool..., but what about the modified 400s? I guess my choices are narrowing down at this point.

[Flight Engineer]

I.F.

I think you need to more clearly set you design goals before choosing a platform and power train.

I would ask myself the following questions at this the conceptual phase:

What weight of equipment do I want to carry?
At what height?
For how long?
Over what range?

What design experiance do I have?
How can I apply that know how to this project?
What is my budget?
What time frame am I working to?

The first set of questions defines the task.
The second define the limitations.

I would then look at how other people have achieved a similar task and how they have failed to acheive it.

only then would I start to consider the platform and the powertain.

Just my two pennies worth.
Hope it helps.

[Italian Flyer]

I.F.

I think you need to more clearly set you design goals before choosing a platform and power train.

I would ask myself the following questions at this the conceptual phase:

What weight of equipment do I want to carry?
At what height?
For how long?
Over what range?

What design experiance do I have?
How can I apply that know how to this project?
What is my budget?
What time frame am I working to?

The first set of questions defines the task.
The second define the limitations.

I would then look at how other people have achieved a similar task and how they have failed to acheive it.

only then would I start to consider the platform and the powertain.

Just my two pennies worth.
Hope it helps.

Ok,, I guess I do have that info, the weight I need to carry is, as I wrote before, a maximum of 280grams , and a minimum of 180 grams, besides the heavy 8 cell nimh 3000mah battery which I believe is almost 300 grams...
so I would say total payload capacity around 600 grams to be safe, excluding the motor/motors, esc, servos and gearboxes.

I want to be able to fly up to 2,000 ft and still see the model, so a 60 inch wingspan should be adequate. The range will be limited by visibility, that's why is probably best to use a conventional layout, and for orientation purposes it's better to have slightly swept wings.

Ground handling is important to me, so a good landing gear is necessary.
I want also a large enough fuselage so that my components will fit inside with room to spare, so I can make adjustments for CG, and make room for more equipement down the road, like video downlink... etc.

My budjet is low... in the sense that I want to use what I have around. I have 2 8 cell packs of 3000mah nimh batteries, so I know I will have to use those... and i do have 4 or 5 speed 400 6v motors , never used.. I do have a astro 020 with a planetary 4.4/1 gearbox, and a kyosho AP29L , the powerplant will have to be one or a combination of those.. of course in the case it's the brushless that will be alone, since it comes with its own speed cotrol. The brushless should be good for 110 watts of power... which would limit my all up weight to roughly 1.2 kg... so that could be the powerplant, but I prefer a larger and somewhat heavier plane for higher altitude and better handling with wind.

Using 4 speed 400 geared 3.3/1 and 10/4.7 apc props, I will have a total of 240 watts out which means I could probably have an all up weight of about 2.5 kg and be happy with it.

As far as kowledge goes, I am not very good with electrics, but I am very experienced with ic powered planes of all kind... biplanes, scale planes , pylon racers, combat planes etc.
I have designed and built several 1/12th scale models with success. I have no problem cutting foam with airfoils of any kind, as long as it's not very critical on construction like most of the mh series airfoils.

I have researched that most of the planes used in lifting competition use a E423 airfoil, which has an extreme camber, I don't know its gliding performance, though I suspect it not to be very good.. slow and stable flight is important to me.. as I do want to take good video...
I have a mini piezo gyro, a gp-03 which I can use on the ailerons to stabilize them a bit and probably help get a bit better footage, limiting the effects of wind gusts.

as far as timeframe, I'd say... 3 weeks should be enough to complete it, since I can only work on sundays and saturday evenings.

I hope it's clearer now as far as design goals.

[Italian Flyer]

I have built a high winger that looks kinda like a c-130 , the wingspan is 64 iches, the airfoil is a E423 high-lift... now I am at the point of having to build the 4 nacelles for the 4 speed 400 with 3/1 gb. My question is: How many degrees of downthrust/rightthrust do I need in the 4 motors? The wing has a 1.5° incidence with the orizontal stab.
Since I'd like to draw the pieces of the nacelles in Autocad before cutting them out of thin plywood and balsa.. I can accurately build-in the down and right thrust needed.
Any comment will be appreciated.

[Tom Harper]

Sounds like quite a project. I would not use any lateral thrust offset on the motors.

1.5 degrees downthrust would set the motors to 0 referenced to the stabilizer.

[Italian Flyer]

thanks, I will post some pics tomorrow.

I have gone to 4 8x6 graupner CAM props now, since they will draw less than 8 amps per motor, so the total draw will be roughly 30 amps. Efficiency is at 70%, which isn't bad at all. All up weight including camera gear, standard servos and the 8x3000nimh pack is projected at 4,5lbs.

[kdwzagi]

I want to be able to fly up to 2,000 ft and still see the model, so a 60 inch wingspan should be adequate.

stretch one of your arms out and make a gap between between your thumb and first finger of 0.060" (1/16") thats how big a 5 footer will look at 2000 feet

i hope you have good eyes

kev

[Italian Flyer]

Well, there's people who have flown their slow stick (48") to over 2000 ft..
I do have 20/20 eyesight.. if that doesn't suffice, I can always use binoculars.

[Italian Flyer]

Here are a few pics of the progress

[kdwzagi]

hi

that looks great, looks like a cartoon scale old timer (no insult meant) i like it

do you hand cut your blue foam?

kev

[Italian Flyer]

No offence taken. Actually there will be the whole nose section to be completed, and that's where the camera will be mounted. I still need to install the LE and TE and ailerons. Also the whole plane will need to be refined quite a bit, I am hoping it will look less cartoon-like once it's done.

I do hand-cut my blue foam with a hot wire bow for the wings and just 2 handles with a hotwire in between that's kept in tension by 2 ppl.'s arms.