Originally Posted by Magne

Hi Geoff.
Have you flown any IMAC sequences with this model/set-up yet?
Have you found that the 4x6s6ah packs have enough energy for two sequences?
I have a similar battery set-up in my own design Zlin 526 AFS with a wingspan of 2600mm (102") and an AUW of 12,3 kg (27 lbs)
I have plenty energy for two sequences Intermediate (almost enough for three sequences) and adequate (with some reserve) for two sequences Advanced.
37 lbs (16.8 kg) is quite a bit more than my model, so I would be interested to hear your results.
Nice model, by the way.
Regards,
Magne

Hello Magne.

I flew my first contest with the Xoar propeller and I was using around 4000 mAh. I have not yet flown in a contest with the new propeller but in practice I am putting back about 3500 mAh in each of the 6000 mAh batteries. I am currently flying Sportsman but my aim was to use this setup for Intermediate.

The power is adequate with the Hacker A100. I originally thought about using an A150 but I wanted to stick with the 12S2P battery configuration.

I had an Unlimited pilot take it for a spin and his only comment was that it flew "very light". I have nothing to compare it to as this is the first 40% class plane that I have flown.

Your Zlin is certainly light! My Hangar 9 35% Extra was slightly more than 32 lbs.

Geoff how do you like the plane compared to the hangar 9 Extra you were flying before? Can you tell a difference?

Originally Posted by super_nova

Geoff how do you like the plane compared to the hangar 9 Extra you were flying before? Can you tell a difference?

I am still getting the feel of it but it definitely flies smoother than the H9 Extra. It also is definitely easier to land as the light wing loading means that I can slow it down with fear of a stall.

I was not able to make the IMAC contest last weekend but I will report again after the next contest.

Subed. Thinking of converting an old aero works 540 (kit built flat stab version) to electric for 3d and IMAC.

Originally Posted by RobT01

Subed. Thinking of converting an old aero works 540 (kit built flat stab version) to electric for 3d and IMAC.

The only issue in converting for 3D and IMAC is that for 3D you want unlimited power but for IMAC you will need to create efficiency to stretch the batteries. Both might be achievable with different propellers.

at my last IMAC contest there was a fair bit of wind. My Slick was a little lacking for power. I have decided to added 2 2S batteries to go 14S2P. I ordered some more batteries but now I need a third charger. It never ends.....

Originally Posted by Geoff Dryer

Well my Hangar 9 Extra is now officially my IMAC backup plane. Over the winter I built a very light 40% class plane from a builders kit with help from a friend who has built many Carden's

Slick 540 (42%)
Wing span 119"
Length 110"

Looking forward to seeing this airframe in person this weekend.

Doug B.

Hard to believe that the IMAC season (and the summer) is coming to an end.

I pushed my A-100 a little too hard a few weekends ago in my 40% Slick.. Apparently I warmed it up a little too much. Anyway the 14S seems well suited to my new A150-10 motor. The 27x12 Propeller is a little bit too slow. I will look for a little higher pitch 27 inch or maybe a 28x12.

While I was waiting for my new motor I practiced with my Hangar 9 Extra I find that it flies almost as well as my 40%!

Bummer about the motor. We'll have to talk A100 props this weekend. I'm mostly interested in 3D performance but you never know, I might end up at an IMAC contest.

Doug B.

Hi Geoff,
Just a suggestion for you.
In my 2.6 meter Zlin I use a Mejzlik 26x15E (electric carbon) propeller.
We are several people in Norway that have concluded that the higher pitched propellers is the way to go for electric IMAC. (Sequence flying, not freestyle.)
I have now built a larger version of the Zlin (3.2 meter, 126") with a Plettenberg Predator 37/6 on 12s24Ah (3x8Ah)
I have tested Engel 30x14 and 30x16. The 30x16 gives superior performance.
There are not too many manufacturers that make high pitched propellers, but Engel have a reasonable selection. Engel propellers have a very low load factor, and would normally require that you go up one size compared to other manufacturers.
Have you any measurement data from your A150 motor with the 27x12, i.e. rpm, Amps, Volts?

Regards,
Magne

Thanks for your comments Magne;

I have not gathered any data from my A150 other than feeling the temperature of the motor and the batteries. After flying 2 Sportsman sequences I am using up between 3500 and 3800 mAh in the 6000 mAh batteries (14s2P). At the last IMAC contest this last weekend I was able to borrow a Xoar 28x12. This was definitely is better than the 27x12 on the uplines.

What if the KV of the motor in youy 2.6 meter Zlin? I assume that you are 12S?

Originally Posted by Magne

Hi Geoff,
Just a suggestion for you.
In my 2.6 meter Zlin I use a Mejzlik 26x15E (electric carbon) propeller.
We are several people in Norway that have concluded that the higher pitched propellers is the way to go for electric IMAC. (Sequence flying, not freestyle.)
I have now built a larger version of the Zlin (3.2 meter, 126") with a Plettenberg Predator 37/6 on 12s24Ah (3x8Ah)
I have tested Engel 30x14 and 30x16. The 30x16 gives superior performance.
There are not too many manufacturers that make high pitched propellers, but Engel have a reasonable selection. Engel propellers have a very low load factor, and would normally require that you go up one size compared to other manufacturers.
Have you any measurement data from your A150 motor with the 27x12, i.e. rpm, Amps, Volts?

Regards,
Magne

Originally Posted by Geoff Dryer

What if the KV of the motor in youy 2.6 meter Zlin? I assume that you are 12S?

Hi Geoff.
The motor in the 2.6 meter Zlin is a Plettenberg Predator 30/8 which has a Kv of 160. This is fairly low, and part of the reason for 15" pitch.
With 12s12Ah (2x6Ah) I get 5700 rpm.
(Mejzlik 26x15E, 5700 rpm, 150A, 6.5kW, JetiSPIN 200 ESC)
This is the set-up that I have used most of this summer.

At the end of the season the batteries lost performance, and I tried a set-up with 15s (3x5s, in a 2p configuration for 15s10Ah. Same propeller.
I used this configuration in a different model the previous two years, and knew it would work well. But I have to dial down the rate on the throttle to reduce the max rpm. (Max. rpm about 6700 rpm, dialled down to about 6000 rpm for 7,5kW power.)

In the 3.2 meter Zlin I have a Plettenberg Predator 37/6, kv=170, Hacker Master Spin 220.
Engel 30x14, 6000 rpm, 230A, 10kW.
Engel 30x16, 5800 rpm, 275A, 12,5kW

With these motors I prefer to use 12s for two reasons:
1. Availability. There is a lot more choice available of 6s packs than of 7s packs, and avoids having to use three packs of different s-counts to make up 14s.
I parallel charge the packs on Powerlab 8 chargers, and therefore like all packs to have identical s-counts.
2. Noise. For noise reasons I prefer to keep the rpm fairly low, and rather use a high pitch propeller. 30" propellers at 6500-7000 rpm sounds like a very sick cow.

Regards,
Magne

Thanks for the information Magne.

I ordered the Mejzlik 26x15E. I will give it a test and let you know the results.

Originally Posted by Magne

Hi Geoff.
The motor in the 2.6 meter Zlin is a Plettenberg Predator 30/8 which has a Kv of 160. This is fairly low, and part of the reason for 15" pitch.
With 12s12Ah (2x6Ah) I get 5700 rpm.
(Mejzlik 26x15E, 5700 rpm, 150A, 6.5kW, JetiSPIN 200 ESC)
This is the set-up that I have used most of this summer.

At the end of the season the batteries lost performance, and I tried a set-up with 15s (3x5s, in a 2p configuration for 15s10Ah. Same propeller.
I used this configuration in a different model the previous two years, and knew it would work well. But I have to dial down the rate on the throttle to reduce the max rpm. (Max. rpm about 6700 rpm, dialled down to about 6000 rpm for 7,5kW power.)

In the 3.2 meter Zlin I have a Plettenberg Predator 37/6, kv=170, Hacker Master Spin 220.
Engel 30x14, 6000 rpm, 230A, 10kW.
Engel 30x16, 5800 rpm, 275A, 12,5kW

With these motors I prefer to use 12s for two reasons:
1. Availability. There is a lot more choice available of 6s packs than of 7s packs, and avoids having to use three packs of different s-counts to make up 14s.
I parallel charge the packs on Powerlab 8 chargers, and therefore like all packs to have identical s-counts.
2. Noise. For noise reasons I prefer to keep the rpm fairly low, and rather use a high pitch propeller. 30" propellers at 6500-7000 rpm sounds like a very sick cow.

Regards,
Magne