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Jmb t7-a (non-xxl)

Old 12-05-2021, 06:45 AM
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RadialWacko
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Default Jmb t7-a (non-xxl)

I know there is an XXL thread, please do not merge/move this thread, mods...

There are very little posts on this plane. I can't be the only one with it... What do you guys think about it? I have a Swiwin 120 I will be putting in it with a 24oz auxilary tank and a Cortex Pro. I am curious how to set it up with the Cortex Pro, but also just curious about flight characteristics. It's a BEAUTIFUL plane. Can't believe there isn't more talk about it. I've only connected the Rx with a battery to test servos, but things seem pretty good. A bit pricey for what it is, but not too insane. Though it is my first composite jet, so I am not really one to be able to talk.

Old 12-05-2021, 05:43 PM
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Originally Posted by RadialWacko View Post
I know there is an XXL thread, please do not merge/move this thread, mods...

There are very little posts on this plane. I can't be the only one with it... What do you guys think about it? I have a Swiwin 120 I will be putting in it with a 24oz auxilary tank and a Cortex Pro. I am curious how to set it up with the Cortex Pro, but also just curious about flight characteristics. It's a BEAUTIFUL plane. Can't believe there isn't more talk about it. I've only connected the Rx with a battery to test servos, but things seem pretty good. A bit pricey for what it is, but not too insane. Though it is my first composite jet, so I am not really one to be able to talk.

I think it's because they are a handful to fly....or so I've heard (which is subjective)....but they are nice.

Let us know how it goes.

David
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Old 12-06-2021, 02:50 AM
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Fudge. lol well It's only my second jet, and it's "on stand by" for next summer. I was recommended it by Dirk and Pacific Jets as a second jet when I was on the phone with him. I never did ask him if he has flown it himself.

I have read it can be a handful with gear down, but that's all I've really been able to find on it's characteristics.

Just out of curiousity, where did you hear that? Like I said, I can't find much of anything about it online.

Zach S
, apparently he has it pretty dialed in with taileron settings and what not. I wonder how much of people saying it's a handful are just winging it with the software configuration. Just looking at it, you can tell it's going to be a nightmare to program. But that's part of the fun, right? ...right, guys...?

Last edited by RadialWacko; 12-06-2021 at 02:53 AM.
Old 12-06-2021, 02:54 AM
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lol nice html, rcu
Old 12-06-2021, 08:25 AM
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My son, Louie, has one. He has a couple of flights on it so far, but the winter has basically interrupted our flying schedule.

We had a lot of problems with the gear. It was unreliable and would often stick in the up or down position. Either way was not good - getting stuck up (usually only one of the mains) has the obvious problems, but getting stuck down wasn't too good either. The main gear doors have *very* powerful digital servos on them, and if they try to close with one of the gear down, things get broken.

We put a Xicoy gear controller on it and did a few minor mods and repairs to the gear and I think we have that worked out, fingers crossed.

That video you posted is Zach Spychalla's model. He has quite a few flights on his. He's using a Flexinnovations Aura FCS on his. I talked to him at length and he actually gave us his setup for the Aura - we're using an Aura 12 Professional on ours. Also, Marco Benincasa, the editor of RCJI Magazine, did a 4-part article on setup and flying of this T-7A model. You should definitely get copies of that and read the article.

Here's the bottom line on this aircraft as I see it. First, its very neutral on the roll axis, maybe even a bit unstable. In addition, the ailerons (flaperons) are large and effective. The combination leaves a plane that is very squirrely in roll - unless you have a gyro on it, which I highly recommend.

Second, the directions mention flaperons and tailerons, but they don't mention how to set them up properly. Here's what they should have said:
- if you use flaperons, you do NOT want any tailerons mixed in when the flapperons are up - normal aileron control is more than enough (with a gyro). If you have tailerons here, hang on for a *wild* ride.
- at 1/2 flapperons down, you still don't want tailerons, aileron control with the 1/2 flapperon setting still works OK. You should set the ailerons to move up more than down though, if your radio can do that
- with full flapperons you MUST mix in tailerons - or you will not have roll control (see Marco's article on his first flight for details).

In the two flights we've had, the first one was done with the gear down all of the time. We did not notice any adverse control actions with the gear down, other than the squirreliness in roll. The second flight, we did pull the gear up. When we did that. the roll issues became even worse and Louie had to turn the gyro on the make it more flyable.

Both flights ended with perfect landings - but Louie's heart was beating pretty fast! :-)

We're looking forward to getting it back out in the spring. Both Zach and Marco's experience show that its a decent flying plane, once its setup correctly. You might want to consider not using flapperons, at least to start out with. There is a flyer down south in Carolina that just got one back in October and that's how he's going to set his up...

Bob
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Old 12-06-2021, 10:48 AM
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Originally Posted by rhklenke View Post
My son, Louie, has one. He has a couple of flights on it so far, but the winter has basically interrupted our flying schedule.

We had a lot of problems with the gear. It was unreliable and would often stick in the up or down position. Either way was not good - getting stuck up (usually only one of the mains) has the obvious problems, but getting stuck down wasn't too good either. The main gear doors have *very* powerful digital servos on them, and if they try to close with one of the gear down, things get broken.

We put a Xicoy gear controller on it and did a few minor mods and repairs to the gear and I think we have that worked out, fingers crossed.

That video you posted is Zach Spychalla's model. He has quite a few flights on his. He's using a Flexinnovations Aura FCS on his. I talked to him at length and he actually gave us his setup for the Aura - we're using an Aura 12 Professional on ours. Also, Marco Benincasa, the editor of RCJI Magazine, did a 4-part article on setup and flying of this T-7A model. You should definitely get copies of that and read the article.

Here's the bottom line on this aircraft as I see it. First, its very neutral on the roll axis, maybe even a bit unstable. In addition, the ailerons (flaperons) are large and effective. The combination leaves a plane that is very squirrely in roll - unless you have a gyro on it, which I highly recommend.

Second, the directions mention flaperons and tailerons, but they don't mention how to set them up properly. Here's what they should have said:
- if you use flaperons, you do NOT want any tailerons mixed in when the flapperons are up - normal aileron control is more than enough (with a gyro). If you have tailerons here, hang on for a *wild* ride.
- at 1/2 flapperons down, you still don't want tailerons, aileron control with the 1/2 flapperon setting still works OK. You should set the ailerons to move up more than down though, if your radio can do that
- with full flapperons you MUST mix in tailerons - or you will not have roll control (see Marco's article on his first flight for details).

In the two flights we've had, the first one was done with the gear down all of the time. We did not notice any adverse control actions with the gear down, other than the squirreliness in roll. The second flight, we did pull the gear up. When we did that. the roll issues became even worse and Louie had to turn the gyro on the make it more flyable.

Both flights ended with perfect landings - but Louie's heart was beating pretty fast! :-)

We're looking forward to getting it back out in the spring. Both Zach and Marco's experience show that its a decent flying plane, once its setup correctly. You might want to consider not using flapperons, at least to start out with. There is a flyer down south in Carolina that just got one back in October and that's how he's going to set his up...

Bob
​​​​​​What you describe is very similar to the F35 I used to fly.
Old 12-06-2021, 12:21 PM
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Originally Posted by rhklenke View Post
My son, Louie, has one. He has a couple of flights on it so far, but the winter has basically interrupted our flying schedule.

We had a lot of problems with the gear. It was unreliable and would often stick in the up or down position. Either way was not good - getting stuck up (usually only one of the mains) has the obvious problems, but getting stuck down wasn't too good either. The main gear doors have *very* powerful digital servos on them, and if they try to close with one of the gear down, things get broken.

We put a Xicoy gear controller on it and did a few minor mods and repairs to the gear and I think we have that worked out, fingers crossed.

That video you posted is Zach Spychalla's model. He has quite a few flights on his. He's using a Flexinnovations Aura FCS on his. I talked to him at length and he actually gave us his setup for the Aura - we're using an Aura 12 Professional on ours. Also, Marco Benincasa, the editor of RCJI Magazine, did a 4-part article on setup and flying of this T-7A model. You should definitely get copies of that and read the article.

Here's the bottom line on this aircraft as I see it. First, its very neutral on the roll axis, maybe even a bit unstable. In addition, the ailerons (flaperons) are large and effective. The combination leaves a plane that is very squirrely in roll - unless you have a gyro on it, which I highly recommend.

Second, the directions mention flaperons and tailerons, but they don't mention how to set them up properly. Here's what they should have said:
- if you use flaperons, you do NOT want any tailerons mixed in when the flapperons are up - normal aileron control is more than enough (with a gyro). If you have tailerons here, hang on for a *wild* ride.
- at 1/2 flapperons down, you still don't want tailerons, aileron control with the 1/2 flapperon setting still works OK. You should set the ailerons to move up more than down though, if your radio can do that
- with full flapperons you MUST mix in tailerons - or you will not have roll control (see Marco's article on his first flight for details).

In the two flights we've had, the first one was done with the gear down all of the time. We did not notice any adverse control actions with the gear down, other than the squirreliness in roll. The second flight, we did pull the gear up. When we did that. the roll issues became even worse and Louie had to turn the gyro on the make it more flyable.

Both flights ended with perfect landings - but Louie's heart was beating pretty fast! :-)

We're looking forward to getting it back out in the spring. Both Zach and Marco's experience show that its a decent flying plane, once its setup correctly. You might want to consider not using flapperons, at least to start out with. There is a flyer down south in Carolina that just got one back in October and that's how he's going to set his up...

Bob
Wow, thanks for taking the time to write all this up! That's a lot of great information. I've talked to Zach, I didn't know he was using the Aura! That's kinda funny because I JUST mounted the one and only Aura8 I have into a plane this week. But I have a Cortex I was going to put in the T7-A, so maybe I will have to take it out... I do like how programmable the Aura8 is. Do you think the professional version is necessary, or will the normal version work?

I could certainly see it being very prone to being squirrely on the y axis. Just looking at the plane, with how small of a wingspan on such a long plane kinda hints at how that could be... But I think that's part of why it looks so cool. It's kinda like a new generation of an F-5 mixed with an F-22 or something like that. I want to see a real one at an airshow! They seem to be pretty capable for being a trainer.

Could you please find out what model xicoy gear sequencer Louie put in it? Would this work? https://www.xicoy.com/catalog/produc...roducts_id=265

Originally Posted by FalconWings View Post
​​​​​​What you describe is very similar to the F35 I used to fly.
Makes sense, as the airframe it's modeled off is for training for 5th generation fighters. Glad to hear it's characteristics are true to life. I did enjoy the F35 EDF I had. Can't wait to try the high alpha maneuvers.
Old 12-06-2021, 10:52 PM
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Originally Posted by RadialWacko View Post
Wow, thanks for taking the time to write all this up! That's a lot of great information. I've talked to Zach, I didn't know he was using the Aura! That's kinda funny because I JUST mounted the one and only Aura8 I have into a plane this week. But I have a Cortex I was going to put in the T7-A, so maybe I will have to take it out... I do like how programmable the Aura8 is. Do you think the professional version is necessary, or will the normal version work?

I could certainly see it being very prone to being squirrely on the y axis. Just looking at the plane, with how small of a wingspan on such a long plane kinda hints at how that could be... But I think that's part of why it looks so cool. It's kinda like a new generation of an F-5 mixed with an F-22 or something like that. I want to see a real one at an airshow! They seem to be pretty capable for being a trainer.
I would NEVER choose an Aura over a Cortex. EVER





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Old 12-07-2021, 12:29 AM
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I have never used the cortex, does it have a lot of programming options?
Old 12-07-2021, 06:30 AM
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Originally Posted by RadialWacko View Post
I have never used the cortex, does it have a lot of programming options?
i guess it depends on the TX you have….if your on Jeti 100% can be easily done right in the TX, cortex pro is all I run and they are great, I did try a few others but I cannot judge the aura, since I never handle one.
Old 12-07-2021, 08:10 AM
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Originally Posted by Desertlakesflying View Post
I would NEVER choose an Aura over a Cortex. EVER
Just curious, but why not? I mean I know the Cortex setup is easy for standard airframes, but why not Aura8? It seems pretty good to me, so far... I've talked with Rocky at Flex Innovations, and they seem very competent over there.

Originally Posted by Dansy View Post
i guess it depends on the TX you have….if your on Jeti 100% can be easily done right in the TX, cortex pro is all I run and they are great, I did try a few others but I cannot judge the aura, since I never handle one.
Cool, thanks. I have Frsky x20. While it's fairly unconventional, so far it has been able to do everything I've asked it to. I really can't find anything the x20 can't do. For $400 it's way up there in quality IMO.

Thanks for the replies everyone, I plan to setup the T7-A in the next month.

Last edited by RadialWacko; 12-07-2021 at 08:23 AM.
Old 12-07-2021, 09:21 AM
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I found the Aura does t play nice with Jeti
Old 12-07-2021, 09:58 AM
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Originally Posted by tp777fo View Post
I found the Aura does t play nice with Jeti
The first gyro I tried was the Aura 8 in an HSD Super Viper turbine foamy. It works great with a Jeti R3. Also have one in the Flex QQ Extra with an R3 that works great. But I would rather do the programming in the Tx as with the Cortex and Jeti Assist.
Old 12-07-2021, 10:57 AM
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Originally Posted by RadialWacko View Post
Wow, thanks for taking the time to write all this up! That's a lot of great information. I've talked to Zach, I didn't know he was using the Aura! That's kinda funny because I JUST mounted the one and only Aura8 I have into a plane this week. But I have a Cortex I was going to put in the T7-A, so maybe I will have to take it out... I do like how programmable the Aura8 is. Do you think the professional version is necessary, or will the normal version work?

I could certainly see it being very prone to being squirrely on the y axis. Just looking at the plane, with how small of a wingspan on such a long plane kinda hints at how that could be... But I think that's part of why it looks so cool. It's kinda like a new generation of an F-5 mixed with an F-22 or something like that. I want to see a real one at an airshow! They seem to be pretty capable for being a trainer.

Could you please find out what model xicoy gear sequencer Louie put in it? Would this work? https://www.xicoy.com/catalog/produc...roducts_id=265



Makes sense, as the airframe it's modeled off is for training for 5th generation fighters. Glad to hear it's characteristics are true to life. I did enjoy the F35 EDF I had. Can't wait to try the high alpha maneuvers.
As far as roll stability is concerned, if you look at the wings, it actually has slight anhedral, which reduces roll stability as well...

No, the Xicoy 12s that you link to isn't the one you want as it doesn't do the doors. You want the LGC13 at least as it does the doors as well. If you go with the LGC13, you'll need the data terminal to set the gear currents and setup the gear doors. You can get them together here:

https://www.xicoy.com/catalog/produc...roducts_id=758

You could also get the LGC15 or LGC19 if you wanted more flexibility and a gyro on the brakes. Whichever you get, get them directly from Xicoy. The "3rd party" versions, like Electron or Prolinks (Dreamworks) do NOT have the same functionality and programmability.

The Xicoy gear controllers that work with the doors have 3 positions that you can set the doors to, gear up, gear down, and gear moving. You'll need those for the T-7A gear. The position for the gear up is obvious. For the gear moving position, you want the doors open as far as the door servos can push them - so that the wheels don't get caught on the doors. However, that works the door servos pretty hard, so for the gear down position, you can let the doors come in a bit towards the gears so that the door servos aren't buzzing and drawing a lot of current. You'll see what I mean when you set the doors up with the Xicoy controller.

Bob


Last edited by rhklenke; 12-07-2021 at 04:48 PM.
Old 12-07-2021, 12:00 PM
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I will probably use same kind of throw values for xxl version as the smaller one uses. With Jeti I just put separate flight modes with different percentages taileron mix.

Slow flight and high alpha may need more throws maybe.
I will be using smoothflite arxl but all programming in tx.
Old 12-07-2021, 12:03 PM
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Originally Posted by rhklenke View Post
As far as roll stability is concerned, if you look at the wings, it actually has slight anhedral, which reduces roll stability as well...

No, the Xicoy 12s that you link to isn't the one you want as it doesn't do the doors. You want the LGC13 at least as it does the doors as well. If you go with the LGC13, you'll need the data terminal to set the gear currents and setup the gear doors. You can get them together here:

https://www.xicoy.com/catalog/produc...roducts_id=758

Whichever you get, get them directly from Xicoy. The "3rd party" versions, like Electron or Prolinks (Dreamworks) do NOT have the same functionality and programmability.

The Xicoy gear controllers that work with the doors have 3 positions that you can set the doors to, gear up, gear down, and gear moving. You'll need those for the T-7A gear. The position for the gear up is obvious. For the gear moving position, you want the doors open as far as the door servos can push them - so that the wheels don't get caught on the doors. However, that works the door servos pretty hard, so for the gear down position, you can let the doors come in a bit towards the gears so that the door servos aren't buzzing and drawing a lot of current. You'll see what I mean when you set the doors up with the Xicoy controller.

Bob
Dirk at Pacific RC also has them. I use this the LG15 controller on all my turbines.
Tone
Old 12-07-2021, 04:45 PM
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Originally Posted by Agrav8ed View Post
Dirk at Pacific RC also has them. I use this the LG15 controller on all my turbines.
Tone
Yes, that's true. There are Xicoy dealers who sell the Xicoy controllers, Like Pacific RC Jets, and those are fine, its just that the "rebranded" ones are setup for the specific gear that they come with and then locked - and Xicoy can't "unlock" them...

Buying direct from Xicoy is easy too, and he ships quickly. All my orders from him came within a week to 10 days.

Bob
Old 12-07-2021, 05:02 PM
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Gaspar can and do unlock the one from proline….it’s his own line of retract (or was I don’t think he still do them 🤷🏻‍♂️) but not the electron (GS200)
Old 12-07-2021, 07:40 PM
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A bunch of knowledgeable people in here! Thanks everyone, I will certainly be getting a new controller. A belly landing with this plane would break my heart.

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