Extreme Flight 76/83" MXS

[ryan_m]

I would love to see some video... so far I'm not thoroughly impressed with the Mejzlik 20x8 that I have on my DA-35/76" MXS.
On the initial runup on the ground I was getting 7400, and after 6 flights today I am now getting 7800 rpm out of it. But pullout from a hover still leaves a bit to be desired, as does the overall op end speed. I think the problem is the damn 64" MXS and ridiculous power/weight ratio that it has. Nothing can match that plane in power, and top end.
I'll say that the 76" MXS definitely pop tops better than the 78" Extra, and is overall a better flying plane (for me). I only managed 6 flights on my MXS today, 3 were motor break in flights, and just putting around at 1/3-1/2 throttle. Then on the 4th flight I couldn't stand it anymore and started trying stuff with the plane. Got some video of that flight that's cooking now. Did several hover pullouts to try and give an idea of it's power. I'll try a few different props next, maybe a 20x9 or Vess 20b. I would have liked a bit more speed, and a bit better pullout.
Also need to lower my expo settings... the plane is so much bigger than the small 64" one that it felt sluggish with my previous/normal expo settings. I'll get that fixed before next outing with it.

 

[gyro]

I would love to see some video... so far I'm not thoroughly impressed with the Mejzlik 20x8 that I have on my DA-35/76" MXS.
On the initial runup on the ground I was getting 7400, and after 6 flights today I am now getting 7800 rpm out of it. But pullout from a hover still leaves a bit to be desired, as does the overall op end speed. I think the problem is the damn 64" MXS and ridiculous power/weight ratio that it has. Nothing can match that plane in power, and top end.
I'll say that the 76" MXS definitely pop tops better than the 78" Extra, and is overall a better flying plane (for me). I only managed 6 flights on my MXS today, 3 were motor break in flights, and just putting around at 1/3-1/2 throttle. Then on the 4th flight I couldn't stand it anymore and started trying stuff with the plane. Got some video of that flight that's cooking now. Did several hover pullouts to try and give an idea of it's power. I'll try a few different props next, maybe a 20x9 or Vess 20b. I would have liked a bit more speed, and a bit better pullout.
Also need to lower my expo settings... the plane is so much bigger than the small 64" one that it felt sluggish with my previous/normal expo settings. I'll get that fixed before next outing with it.

[MENTION=2685]ibcinyourc[/MENTION] has a falcon 20x9 already drilled for $56 bucks... Maybe you can try that one

 

[skibum44]

I think the problem is the damn 64" MXS and ridiculous power/weight ratio that it has. Nothing can match that plane in power, and top end.

My 4330 on a 10.25lb plane rivals the 4315-480 in my 60" EXPs... Might even surpass. Need a size between the 4330 and 5335 to get close to the performance in a 12.5lb plane, IMO. Interested to see how the 35 performs after broken in, but I think it will leaves some to be desired, especially with a 20" prop on a 76" bird.

 

[Aeroplayin]

I would love to see some video... so far I'm not thoroughly impressed with the Mejzlik 20x8 that I have on my DA-35/76" MXS.
On the initial runup on the ground I was getting 7400, and after 6 flights today I am now getting 7800 rpm out of it. But pullout from a hover still leaves a bit to be desired, as does the overall op end speed. I think the problem is the damn 64" MXS and ridiculous power/weight ratio that it has. Nothing can match that plane in power, and top end.
I'll say that the 76" MXS definitely pop tops better than the 78" Extra, and is overall a better flying plane (for me). I only managed 6 flights on my MXS today, 3 were motor break in flights, and just putting around at 1/3-1/2 throttle. Then on the 4th flight I couldn't stand it anymore and started trying stuff with the plane. Got some video of that flight that's cooking now. Did several hover pullouts to try and give an idea of it's power. I'll try a few different props next, maybe a 20x9 or Vess 20b. I would have liked a bit more speed, and a bit better pullout.
Also need to lower my expo settings... the plane is so much bigger than the small 64" one that it felt sluggish with my previous/normal expo settings. I'll get that fixed before next outing with it.

Thanks, Ryan. Nice write-up. For pull-out, you may want to try the Vess 21A if the engine can swing a little more D. The weight and the higher D/P ratio will help, especially if the engine can spin it up a little faster and stay running. The problem will then remain top end speed, but that will depend on the RPM change. I'd try a lighter beech prop with the same pitch before going CF, then go to a bigger diameter with the same pitch with a beechwood second. A heavier CF with a deeper pitch would be the last option for me, but you never know with a new engine. Especially a DA with a short stroke that likes the mid-range.

 

[ryan_m]

Video is up! No music, youtube has changed the way you add music and I haven't had a chance to figure it out. Running out the door to take the kids to the pool, so that will have to wait! At least you can clearly hear the motor during the 2-3 hover pullouts that I have here.

[video=youtube_share;gSW6a_fnQJE]http://youtu.be/gSW6a_fnQJE[/video]

 

[Enterprise]

All my prop experience is from the VVRC40 so far in this size. Mej 21x8 is a wonderful 3D prop, but leaves a bit on the table the top end. The 20B is pretty nice, but the noise is always getting me ire from the clubs. The Mej 20x9 is fast, but lacks in 3D performance. I have never liked any A prop from Vess. I have tried a few like 20A and 25A. I have a PT 21x10 carbon to try on the twins, but I never seem to get around to it.

My main issue is that I have out grown the 71 slick the DA is on, so I don't get very motivated to bring it.

I am chomping at the bit now to at least start building my MXS. I have servos scrounged from other planes, so I just need to get assembling.

Greyhound still has not found my 92 wings, nor have they given me any money, even though I agreed to their paltry settlement. My time is more valuable than wasting it on tracking down some pennies from them.

 

[Aeroplayin]

Greyhound still has not found my 92 wings, nor have they given me any money, even though I agreed to their paltry settlement. My time is more valuable than wasting it on tracking down some pennies from them.

That sucks, and I'll have to remember that if I ever think about doing it again.

 

[3dRCparts.com]

Ryan, did you get the larger or smaller jtec pitts

 

[Aeroplayin]

Video is up! No music, youtube has changed the way you add music and I haven't had a chance to figure it out. Running out the door to take the kids to the pool, so that will have to wait! At least you can clearly hear the motor during the 2-3 hover pullouts that I have here.

Thanks Ryan. The pull-out really helps me make some comparisons. That pull out was just about the same as my 10S setup with the 21x10 Falcon electric beech (E-1) and the A60-7S on the 78 Extra gas version converted to electric, so about 13 pounds 10 ounces. But I'm getting a little more airspeed wit the 10 pitch. This is Tom flying that plane, and you can see the full vertical pull out comparison at about 4 minutes, so the batteries have been stressed a bit already. The static RPMs peak at about 6480 and the in-flight RPMs peak at about 6750. The A60-7S has an unloaded Kv of about 225.

[video=youtube;cRXHp0cwlJk]https://www.youtube.com/watch?v=cRXHp0cwlJk[/video]

 

[ryan_m]

Ryan, did you get the larger or smaller jtec pitts

I have no idea, the part number on the DA invoice is EJT35P if that helps any.