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Jun 14, 2015, 11:14 AM
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Originally Posted by pavlis
watching the landing that Kevin did, I realised that she couldn't keep her nose up for high alpha landing. Maybe she is nose heavy Maybe she just needs some compensation trim after the landing flaps. but the landings were pretty fast. I can't imagine how she will land with that CG and a heavier Turbine setup that Daniel did with 1.5liters of fuel + smoke + lights.

we all saw lots of L-39s and this is one of the lowest wing loadings. I think she should be able to land slower.
Hi Pavlis, I don't think the plane is nose heavy; I was simply landing too fast because I was still trying to get used to the plane, and whenever I'm not familiar with a plane, I always compensate by landing too fast rather than too slow because I don't want to risk stalling the plane. Now that I'm more familiar with the plane, you can bet I will start coming in slower

Will hopefully shoot some new videos this coming week.

Kevin
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Jun 14, 2015, 12:42 PM
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Originally Posted by kchen95
Hi Pavlis, I don't think the plane is nose heavy; I was simply landing too fast because I was still trying to get used to the plane, and whenever I'm not familiar with a plane, I always compensate by landing too fast rather than too slow because I don't want to risk stalling the plane. Now that I'm more familiar with the plane, you can bet I will start coming in slower

Will hopefully shoot some new videos this coming week.

Kevin
Hope that's the case. because even after take off (forgive me if I'm wrong) I could see the plane pitching down a bit. . because the team of five is already built with everything. I preferred to fly the first model as light as possible but building all the planes together was easier.
Jun 14, 2015, 03:33 PM
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I though I have posted these photos before but I don't know why I didn't ..
so here is the link to the post.
https://www.rcgroups.com/forums/show...6&postcount=35

Dani have chosen to remove some of the ducting.. CNC cut formers and fitted cola bottles for fuel.
I already sent the measurements to create the fiberglass fuel tank though. will create conversion kits in one box. the tanks will come with fitting tubes and clank and already prewashed. ready to use.
Jun 22, 2015, 08:54 AM
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So, I'm getting this plane more dialed in now - please see below a compilation video of two flights from today.

Some additional info and observations, now that I've flown it about 10 times:

1) Weight without any batteries is 5.8KG, so AUW would be 7.5KG to 8+KG, depending on the size of batteries. So far I'm using 12S 5500 packs, so my plane's weight is around 7.5KG.

2). Using flaps definitely help smooth out the takeoff so that you don't get the "jump".

3). It is a super slick, powerful plane with unlimited vertical - the video will make that obvious.

4). On the other hand, I do not recommend this as a starter 120mm plane, as it is much more agile in the air than more docile planes like the JTM Viper and XXX. It also takes more precision to land than the Viper and XXX, both of which will just glide down after you chop the throttle. With the L39, you have to focus much more on the speed, angle and flare for the landing. I'm still experimenting with various CG, speed, elevator input/etc to try to get the best angle and speed of attack.

Will share more once I figure out more things about this plane.

Kevin


JTM L39 compilation (5 min 21 sec)
Jun 23, 2015, 09:06 PM
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Three more flights today and I figured out something else - this plane requires a relatively faster landing speed (relative to the Viper) to come in and still maintain decent elevator control. Once the plane is too slow, the elevator becomes very pitchy. So, need to fly it like a jet and fly it to the ground.

Kevin
Jun 23, 2015, 11:42 PM
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Just not INto the ground hehe
Latest blog entry: Extreme RC AUSTRALIA
Jun 25, 2015, 12:17 AM
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Originally Posted by Extreme_RC
Just not INto the ground hehe
Haha yes Definitely getting better - see takeoff and landing video from this morning's flight.

Kevin

JTM L39 takeoff and landing (0 min 51 sec)
Jul 06, 2015, 11:19 PM
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Finally got comfortable enough with the plane to fly it with bigger batteries today - 12S 8700. Happy to report that the plane handled the extra weight just fine - see the flight video below.

Is no one else flying this plane? Would love to see reports/impressions from others!

Kevin

JTM L39 12S 8700 flight (4 min 51 sec)
Jul 06, 2015, 11:32 PM
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very nice Kevin.
did you use the same throws on your elevator and same cg?
Jul 06, 2015, 11:36 PM
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Thanks Pavlos! Same CG (110mm); elevator reduced by about 3mm (17mm).

Kevin
Jul 07, 2015, 12:13 AM
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that's good ! fuel tanks should arrive shortly btw
and new fuel tanks for the L-39 should also be available soon.. again without having to cut the inlets
Jul 07, 2015, 12:40 AM
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Thanks Pavlos! Really appreciate your kind gift!

Kevin
Jul 11, 2015, 01:28 AM
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Received the red L39 this week - another beauty! Planning to use a Jetfan 120 on this one.

Kevin
Jul 11, 2015, 06:43 AM
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Mannyman535's Avatar
I like that one Kevin, can't to see that one in the air
Jul 11, 2015, 07:01 AM
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icicles's Avatar
Very nice,looks superb just sitting there.

Chris


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