RCU Forums

RCU Forums (http://www.rcuniverse.com/forum/)
-   RC Warbirds and Warplanes (http://www.rcuniverse.com/forum/rc-warbirds-warplanes-200/)
-   -   CY Model Lavochkin LA-7 (http://www.rcuniverse.com/forum/rc-warbirds-warplanes-200/11635402-cy-model-lavochkin-la-7-a.html)

Hot Rod Todd 02-22-2017 06:18 AM

2 Attachment(s)
We had some unseasonably warm weather in February, so I was able to get the LA-7 out for a maiden flight. The DLE-120 ran perfectly from the first time I started it up, so after a few minutes of running I put the cowl on and got ready for the first flight.

It was a nice day, with a little wind right down the runway. I fed on some power and the LA-7 jumped into the air a bit early. It was not a problem, since it seems to fly very light at 38 lbs. A couple clicks of elevator and aileron trim, and it was flying hands off. I tried to put the gear up, but it didn't want to respond. I think the angle of the gear doors was keeping them from going up. I had air after landing, so I'll need to do some work, also open up the circuit to speed up the gear and help the cause. Flying around with the gear down I didn't get a chance to check out full throttle speed, I didn't want to rip off the gear doors or something. It moved along well even at half throttle with the gear down. I had a bit too much throw on the elevator, and it was a bit hot even at low rate. The aileron rates were good, with medium being about right. I set up for landing and came in with about 3/4 flaps. It seemed to want to float a bit, and my extra elevator throw didn't help the situation. I throttle up and went back around after I lofted it a bit. On the next landing I had it settled in pretty nicely. It went over on it's nose right away due to one of the struts turning. Dropping on it's nose didn't do much damage to the cowl, and the prop will be OK with a bit of sanding on the tips.

All things considered I was happy with it. It flies really well. I'll have to get the gear issues figured out, but that's not uncommon for retracts. Hopefully once I get the gear working right it will not have the tendency to nose over on landing. I may be able to take out a bit of the nose weight to help the nose over situation, I won't know for sure until I get the elevator rate set better and do some stall testing. It didn't help that the runway was very soft and made the wheels drag like pushing through mud.

Here's a couple of photos at the field. No in-flight photos yet, but I'll have some this spring I'm sure.

http://www.rcuniverse.com/forum/atta...mentid=2202298http://www.rcuniverse.com/forum/atta...mentid=2202299

TimD. 02-22-2017 06:20 PM

Looks good. I have the big Dauntless with a moki 180 in it, I should get it maidened within the next few weeks.

Hot Rod Todd 04-24-2017 07:12 AM

4 Attachment(s)
I was not happy with the geometry of the stock gear mounts, so I decided to dig into the wing and modify them. At the same time I switched to gear made for the Anderson LA-7 that has a more scale length and additional power.

I had uncover the wing and add some new structure. It wasn't that hard to do, but it took a while. I didn't even bother removing all of the old mount. Just cut some of it out of the way. This photo shows the new position in relation to the stock. By changing the angle I'll be able to get the gear much farther forward and it will still fit into the bay.

The end result pulled the wheels forward a couple inches.

Hot Rod Todd 04-24-2017 07:37 AM

4 Attachment(s)
Once I got the gear doors mounted I took it to the field for the second flight. The ground handling was much better, and my gear came up without incident. The 26x12 prop pulls it around at good speed, and it even moves out well at half throttle. I had something happen to the gear angles on landing, I'm currently working with Century Jet to get them resolved. If I can gain confidence that it won't nose over I'll be trying a 25x12 three blade instead of the two blade. Here's a couple photos of it with the new gear at the field.

n8622t 06-23-2017 05:57 AM

great work!!
 
WOW Todd!! got in late on this thread, glad to see this model since i picked one up. I sent you a message so keep up the good work its awesome!
jimmy

n8622t 06-27-2017 07:03 AM

Just getting started
 
Pulled gear out and got the factory struts polished down with 180 grit to fit the Robart 635RS retracts

n8622t 06-27-2017 07:06 AM

Someone will have to tell me how to post pics in this new RCU format....sorry

Hot Rod Todd 06-27-2017 07:20 AM

Use the "Post Reply" button. There's a manage attachments button that allows you to post the images. Once you click it you'll see, it's not too hard to do.

n8622t 06-27-2017 09:11 AM


Originally Posted by Hot Rod Todd (Post 12347884)
Use the "Post Reply" button. There's a manage attachments button that allows you to post the images. Once you click it you'll see, it's not too hard to do.

Thanks Todd

n8622t 06-27-2017 09:21 AM

6 Attachment(s)
http://www.rcuniverse.com/forum/atta...1&d=1498584006

warbird04 07-27-2017 10:24 PM

Hello,

I finish my own La-7 cy models, and I want to say witch blue color do you have take?
I search in the Revell and Humbrol color, but nothing fit the color.
Do you have an information for me?
Thanks

warbird04 07-27-2017 10:32 PM

La-7 cy models gear relocation
 
6 Attachment(s)
Hello every body,
I post you some pictures of my La-7 cy models gear relocation solution. The angles are scale, I self made my struts and covers to. With this issue, there is no nose over, and the 6" Wheel help for handling.

warbird04 07-27-2017 10:36 PM

On youtube you find an short video of my gear in progress....

I hope that helps other people who want to relocate the gear.

Hot Rod Todd 07-28-2017 04:43 AM

4 Attachment(s)
Nice job on the struts warbird 04, relocating the gear is almost a requirement on this plane if you want to minimize nose over. I put a carbon fiber 3-blade on mine, so damaging that is not fun.

The paint I found that matched is Krylon Aqua. It comes in a spray can and is a very close match.

warbird04 07-29-2017 07:12 AM

Thank you, but do you have a color nummer, or a color name? That helps me to order this spray...

Hot Rod Todd 07-31-2017 04:36 AM

I don't have any special number or name. If you can get Krylon, the name is as I said. Here's a link to buy it at Walmart.com.

https://www.walmart.com/ip/Krylon-Co...&wl13=&veh=sem

warbird04 08-04-2017 12:07 PM

Thank you for the link...
You have got an incredible job, nice result, congratulation.
What is your final in flight weight?

Hot Rod Todd 08-04-2017 12:16 PM

2 Attachment(s)
I didn't weigh it, but it flies like it's pretty light. I'll have to lift it onto a scale sometime and see what the all-up weight is. I'd guess right around 31 lbs.

taildragger21 08-04-2017 01:05 PM

4 Attachment(s)
I'm really enjoying my Cy la7. The saito Fg84 flies it actually really well

warbird04 08-04-2017 11:28 PM

Ok Taildragger, can you give me more info about your LA? as the full in flight weight, the prop size and the rpm (read after 15 seconds at full throttle), is the Fg84 stock or modified, and what opening have you made to escape the hot air from the motor?
Thank you that will helps a lot.

taildragger21 08-05-2017 02:25 PM


Originally Posted by warbird04 (Post 12357629)
Ok Taildragger, can you give me more info about your LA? as the full in flight weight, the prop size and the rpm (read after 15 seconds at full throttle), is the Fg84 stock or modified, and what opening have you made to escape the hot air from the motor?
Thank you that will helps a lot.

Haven't weighed it. I'm kinda thinking like Todd in that it's probably 31 lbs or so. The fg84 is bone stock. It did run terrible with no transition until I switched from 6.6 a123 to 7.4 lipo on my ignition. Now the transition is good and top end is much better. Swinging a 24x10 fieala prop at around 6700 rpm. The cooling from the cowl exhaust is close to enough. I added a cooling louvre to the top of the cowl for more air exit for the top cylinder.
love this airplane

warbird04 08-05-2017 10:45 PM

Thanks for the infos...but I am surprised that nobody weight his airplane.... The weight of an airplaine is a important point, this is the power / weight factor that characterize an véhicle or airplane capacities.
But tell me, do you have add some weight in the nose for balancing? Do you have you make some vidéos on youtube?

Patrick R. 04-28-2019 04:18 PM

ARF'S are assembled. Kits and scratch built are builds....

racer-mech 09-07-2019 02:12 PM

Hello All, it's been great to read this thread. However, with the gear issue, did you guys change location only for scale appeal/appearance, or did you need to change the angle to prevent nose over?

Cheers

Patrick R. 09-07-2019 03:09 PM

racer-mech.

I have built the Dave Anderson design LA 7 his plan had the gear in the scale location and used Sierra retacts they were also pretty close in scale. Installed them with no modifications and not have had any problems with nose overs. Powered with a DA 100 had to put 4.25 lbs up front for balance..


All times are GMT -8. The time now is 05:49 PM.


Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.