Hey everyone, so I don't have the APM tuned very well but at least its hitting waypoints and holding altitude and airspeed. I decided to get it flying and see just how long it would go. Here it the result:

here are the Tlogs

this is the equipment list:

Techpod Kit

Foxtech 370kv motor

APC 12*8 prop

Castle ice2HV 40 ESC

2x Zippycompact 6s 5000 mah lipo

APM 2.5 + telemetry + airspeed sensor

AttoPilot 45A current sensor

6x Hitech 65-hb servos

So whats next for the techpod? well, I will refining the gains. After I have it flying smoothly, I have a setup in the works that will be pushing flight times over 5 hours. Stay updated on the lated techpod news @ hobbyuav.com


Views: 12221

Comment by Reto Buettner on September 10, 2013 at 1:18am

@ Joe: Thanks for the indication. I am well aware of the Flexrotor. See my post on July 30. I like the approach, but it seems to be quite difficult, they havn't published any progress since two years. I am more than happy to hear if this technology makes it to market.

The Quadshot of TransitionRobotics is another interesting VTOL design.

Cheers, Reto

Comment by Reto Buettner on September 10, 2013 at 4:22am

@ Joe: I just found that the newest progress of aerovel is on Youtube, not on their website. Why they don't update their website is not clear to me. They seem to be making some progress, which is nice.

Comment by Gary Mortimer on September 10, 2013 at 4:47am

Yes if you look on the sUAS News feed on the right of the front page at the moment you will see they have been flying it this week.

Comment by Reto Buettner on September 11, 2013 at 1:13am

That is exactely how I noticed :-)

Comment by moglos on October 3, 2013 at 4:17am

Gruezi Reto

I've been trying your advice above in ecalc and I'm having trouble getting good results based on your rules of thumb (on page 4 of this thread).

I'm flying a Bormatec Maja 2.2m wingspan with AUW of about 2.5kg, 3 cell, cruise speed of about 40 km/hr at 75 watts using a 10 x 5 or 11 x 6 prop. I blew up my Turnigy SK3 3530 1150kva motor today (overloaded it with the 11 x 6 prop on takeoff) so I'm looking for a new motor.

My problem with ecalc is that if I use a prop with a pitch ratio of 1 I can't get the maximum power and pitch speed at 100W/kg and at a bit less than double my cruise speed like you recommended

Is there something I'm missing?

Comment by Reto Buettner on October 6, 2013 at 11:18am

The Maja is aerodynamically not efficient. Therefore I suggest to adjust the rules of thumb:

1. Prop pitch ratio at 0.75 (lower)

2. Pitch speed a bit under double the cruise speed (unchanged)

3. Propulsion power around 150W/kg (higher)

You are looking for 350W and a pitch speed of about 80km/h. The following setup might work well:

Prop: 14x9

Motor: 680kV

In your case this would be a larger prop. This is special, as your starting point is a very small prop for the given weight. A standard motorglider like an Easyglider equipped with a 10x5 prop weighs only 1kg.

And: Consider replacing your Maja. There are a lot more efficient and better mannered airframes around.

Comment by moglos on October 6, 2013 at 2:26pm

Merci vielmal

Thank you for your input, I'll give that a try.

You're right about the aerodynamics of the Maja.

Can you recommend a more efficient and better mannered airframe? I do like the payload/lift capacity of the Maja, but I don't really need that much. I like the Techpod but it doesn't seem to have much space at all.

Comment by Reto Buettner on October 7, 2013 at 1:52am

Concerning the airframe you must first define your requirements:

- Weight and size of payload?

- Forward view required?

- Endurance in time and distance?

One of the following will probably meet your requirements: If you don't need forward view, then I would go for a motorglider, like the Solius, Cularis or Hobby King ASK21 EP Glider 2600mm Fiberglass. They are efficient and well mannered. If you need forward view, you might choose the Techpod, the Skywalker X8 or the RVJET.

Comment by moglos on October 7, 2013 at 3:26pm

Hi Reto

Thanks for those tips. Forward view isn't required. Payload would be one (or two) compact cameras pointed straight down, roll stabilised. 60-90 minutes endurance would be good, 120 minutes would be great. At around 40-50 km hr. 

I fly my Maja with a roll stabilised NEX5 (or Canon S100) mounted sideways (landscape) under one wing. It makes my aerodynamics even worse, but the fuselage just isn't big enough.

I expect I'll have to keep it under the wing because I don't think any of those airframes would have the room.

I like the look of the ASK21 fuselage space, but the wing is quite low so I couldn't mount a camera under the wing. I probably could create a bracket to mount it in front of the wing, or within the wing even. 

I like the Techpod too. There is a new one called the Cyclops which is available in fibreglass and has much more payload room. (It sounds like the original Techpod team had a disagreement and now they are now both making their own planes based on the same design.)


Comment by Reto Buettner on October 8, 2013 at 3:53pm

For 120min endurance an efficient airframe is required.

You don't need forward view, go for a motorglider airframe. You can choose from a wide variety of models, they are very efficient and good mannered.

Don't try to mount your cameras in free air, e.g. under the wing. They will act like giant air brakes and will destroy the efficiency of your airframe. I tried it. Additionally they are vulnerable when landing. Mount them in the fuselage.

You have rather large payload, especially if you want to fly with not just one but two cameras. Your airframe needs a large fuselage. Scale gliders meet that requirement.

The Hobby King ASK21 EP Glider 2600mm Fiberglass might be a good and cheap choice. You can also consider the Roke ASW 17 E.

Or you can mount a motor yourself in the nose of any scale glider:




All articles are in german.

Alternatively you can choose a high performance glider and build a camera case underneath it. Like the aeromapper.

Let us know when you have build your plane and achieved 120 min endurance with electric propulsion carrying two roll stabilized vertical cameras. Quite a challenge, not many people have done that before.


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