7th Ponty Fly In - Mystery Model

[PaulJ]

Finished and flown........ It came out a bit heavy at 8.8oz including (unfortunately) some weight in the nose. Luckily I read the stuff about lack of rudder response before adding the fin (thanks chaps!) so I made the rudder much bigger than standard and have ended up having to reduce the movement!

It flies "ok" but because of the weight it seems to be only just above the stall most of the time and drops a wing all too easily........

Then it dawned on me to try the much repaired wing of my "Poppet"..... Same chord, same dihedral but 32" span and somewhat lighter........ All up weight 7.7oz

It flies much better! I guess it is what you might call a "Pop Star"!

Paul

[Martin]

Looks good!

I fear my Pulstar may also turn out a little underpowered. I've not flown it yet, but the wing does seem rather heavy: like Paul, I've compared it to another existing wing (from my Cardinal) and thought that it will probably fly better with that - the Cardinal wing is lighter and a bit bigger area.

I can't think of such a catchy name as Pop Star though. Card Star? Pulsinal?

[Shaun]

Like the modification Paul. Did try flying the original model with a 3s Lipo?

Shaun

[_AL_]

Looks good.
Mine has come out at 202g (A bit over 7oz) balanced & RTF.
I stretched my wing by 2" & I'm glad I did now. I also increased the rudder size by around 15-20%.

Unfortunately I also look like having power issues. With the 3035 4 blade & 2s I'm only getting 15W which comes out around 37W/pound. I was hoping for around 45-50W/pound.

I could go to 3S but that'll probably be too much & also make it heavier.
I'll hunt around for some 3040 or 3045 props which would probably give me the extra 5w I need, if I can find some.

I took some pics with my good Nikon but still it looks Blue. It's actually very Green. I'll get a pic in sunlight when I eventually get home before dark.

Al

[Shaun]

Hi Al,

Another nice looking model.

Which motor are you using? Mine is an Turnigy 1811 - 2900Kv . The prop is a DAL HQ 3 x 3 x 4. Your reading for the power seems very low...

Have you ranged the esc so you get full output ? Out of the packet my 6A Turnigy esc (with the 3 x 3 x 4 prop) gave 17W... after ranging it I got 22W on a fresh - off the charger standard 2S LiPo.

On a 2S - 500mAh HV LiPo (1.1 ozs) I achieved 26 W and on a 3S - 370mAh LiPo 43 W (1.25 ozs)

The photo of it flying was on a 2S - 450mAh LiPo (1.1 ozs)...... Model weight is 5.95 ozs excluding the LiPo (which including the LiPo is approximately the same as yours). It didn't need full throttle to maintain height, there was plenty of power for the model type.

My wing weighs 1.7 ozs. For steering I am using a heavier Tobe Adams pulse propo unit. You would save additional weight with a sub 5g servo but I wanted the flappy experience.

I can see why Pauls is responsive, that's a huge rudder


I hope this helps.

Shaun

[_AL_]

Thanks Shaun.
Same motor & esc with a 460 2s battery.
I'll try ranging it tomorrow. It is an old motor out of a crashed foamy so it may be dud motor but usually that means more watts used for less thrust. I'll replace that last.
My Props are 3x3.5 4 blade Gemfan units. I found some 3x4.1 4 blades so I'll order those & see if they are any better.
It's not a big deal & I'm sure I'll work it out. The biggest issue right now is finding a day with light wind where I can get away & have a fly.

Al

[Shaun]

From years of flying quads I've personally found that the DAL props are the best. Always balanced, and accurate on pitch, the Gemfan less so. If you can get Bull Nose versions you will have a little more blade area at the tip.
Good luck with the flight.

Shaun.

[_AL_]

It turned out to be a battery issue.
I used the battery out of one of my tx. Unpuffed & works fine in the TX but being left charged must have pushed the internal resistance through the roof.
Same setup with a different battery gave me 19.5W.

That'll do me. She's good to go.

Al

[Shaun]

Hi Al,
It should fly fine on that. Enjoy..

Shaun.

[Martin]

Test flew mine this morning. I stretched the wing a couple of inches compared to the plan and enlarged the fin and rudder about 25%, It weighed in at 216 grams (7.6 ounces) - but that will rise a little when I complete the modifications mentioned below.

The balance point came out as shown on the plan - quite far back on the wing. First test flights it was over elevated and stalling. We eventually added a full 3/16 inch (about 5mm) of packing to the trailing edge of the tailplane - it's bottom mounted so this is like applying down elevator. Even with that it was still stalling so I borrowed a bigger battery from Mike (1000 mAh instead of 500 mAh) to increase the nose weight and move the c.g. forward a bit - it's still a bit aft of where I'd put it if I were designing the model.

Then it flew quite nicely. Adding power makes it climb and adding power quickly can induce a stall. It has the pulser rudder with quite a large area and throw - with that the steering response is adequate, but this is not a model I shall be attempting intentional aerobatics with!

So the required modifications before the next outing are adding the tailplane packing more permanently and neatly, fitting a bigger battery or some nose weight, and making a hatch to cover the battery compartment (accessed through the top of the nose under the propeller) - I didn't bother to make a hatch till I know that it flies okay.