yee-ha

Sweet! If this plane turns out to be a proven flyer, then consider your first kit sold. I love the Lagg-3! Skyshark RC was suppose to be working on a Yak-9 and I guess it was sent back to the drawing board. I am glad there is someone else in the world who likes Russian WWII stuff as much as I do.

Chad Veich

My Feedback: (60)

Mike, first off let me say that I think your choice of airplanes here is fantastic. The Lagg, just like your previous Yak, is a great looking airplane that is way too overlooked. Here is my .02 cents concerning your design ideas above:

1. I hate mechanical retracts. This is strictly a personal opinion though and, since you are doing the designing, you can choose whatever retracts you like best. Should I decide to build one it is a simple matter to install pneumatic retracts in place of the mechanical ones. Personally, I would like to see it set up for Spring Air gear but I have no idea what the majority of modelers prefer when it comes to mechanical or air retracts. Maybe a poll is in order?

2. My guess is that 8 out of 10 modelers will install two aileron servos but, for those that prefer, having a single servo with bellcranks shown on the plans is fine. Servos are too compact and too cheap these days to bother with the hassle of all that linkage but, again, that's my preference.

3. I like a single servo (heavy duty) on my flaps. No reason to tempt an assymetrical flap situation with dual servos if you don't have to.

4. Pull-pull on the rudder is also my preferred method, parallel tailwheel hookup is fine so long as it works with your particular retract unit.

5. Your method of elevator hookup is also my standard operating procedure. Just make sure your control horn is SECURE, especially if the unit cannot be accessed for inspection and maintenance. I always silver solder mine.

6. An in cowl muffler would be great but, keep in mind, alot of folks have had overheating problems with the TF in cowl mufflers.

I will be watching this post in anticipation, good luck with it. Regards, Chad Veich.

dlcarterjr

I'm building that exact plane right now from the Model Aviation plans, except I'm converting it to R/C. I'll post some pix in a separate thread as I get further along if anyone's interested.

mihaj

Hi group,
WOW,
Thanks for all your feedback.

How are you Chad?
I really like the way you replied. So here is my answer.
1. The reason for me to use mechanical retracts is the cost difference. I was thinking about Spring-Air and I don't think there will be a problem installing them on this model. The only thing is that you can't use their oleos without adapters or modifications (LG should be bent forward 15° to be scale.) It is easy to do on wire LG though.
2.I will evaluate aileron servo option one more time. I like two aileron servos setup better myself. At this point the only servo that will fit is Hitech or equivalent aileron servo which is a little pricey. (extra expense for potential modelers?)

Thanks for your attention to this project.
Check back for more!
Regards,
Mike.

Here is a frame work for fuselage

LA7flier

My Feedback: (1)

LaGG-3...early 1940's fighter design. Russian nickname "guaranteed varnished coffin"...woefully underpowered, slow to climb and accelerate, poor handling characteristics but available in some numbers by the time the Germans invaded. Poor quality control caused most Russian pilots to fly with the canopy open since they feared being trapped inside due to a jammed canopy. Lousy dogfighter due to it's vicious snap charactistics....LA-5 and LA-5FN were far superior aircraft and further refined with the intrioduction of the LA-7 in 1944

mihaj

Yes, this is true. It is sad that history remembers only bad things about this aircraft. Unfortunately, almost none of available sources are saying that this airplane was the first step for many of Soviet fighter aces that started their victory counts flying LaGG-3. Furthermore, a far superior La-5 is nothing more than LaGG-3 equipped with 9 cylinder radial engine that was used on Su-2.

Anyway, this are all history facts and they can not be hidden and I don't think that bad reputation of LaGG-3 will stop me from ceating a great flying replica

Cheers,

Mike

Oryx

Mihaj, like you I don't think that the bad reputation should influence your decision to build the LaGG-3. In my opinion, the LaGG is actually a very good-looking airplane, and it has a certain character that should make it stand out at the flying field.

Of course, what La-7 wrote is quite true. Although, the dislike for the LaGG-3 doesn't seem to be completely universal, and much of its bad reputation was linked to both the aforemention bad quality control and also bad maintenence in the field. Both these things were, however, addressed in time and apparently there were great improvements from the early serie to the later ones. For instance, going from the 1940/41 production models to the later 1942 production models, the LaGG kept loosing weight (except for the one with the 37mm cannon that gained some weight again). Performance also increased steadily as the design evolved from the early models to the later ones, although, as mentioned, it took the introduction of the M-82 engine to really put it on par and later past that of its German opponents.

As mentioned by Mihaj, the LaGG-3 was also the fighter on which many of the Soviet Union's finest fighter pilots scored their first kills. These include people like Skomorokhov (46 personal + 8 shared kills, 1st kill in LaGG-3, rest in La-5's and La-5FN's), Popkov (41+1, first 5 kills in LaGG-3), Kamozin (35+13, many in LaGG-3's), Kostylev (11+32, apparently most if not all in LaGG-3's) and many others.

So, no doubt this aircraft played an important role in history and its about time someone does it justice. I wouldn't mind doing one myself, although I must admit that my favorite in the Lavochkin series (in terms of looks), is the La-5F and La-5FN.

Cheers,
Bennie

mihaj

Thanks Benny,

Welcome back!

How is your PhD doing?


BTW: I have couple of questions for you.

1. I designed the wing with Clarc YH root and Clarc Y 11.7% tip which will give me some washout. Any concerns?
2. What in your opinion the incidence should be?
3. How about thrust line angles if any?

Thanks

Mike

Oryx

Hi Mike

Thanks. Yes, I am done with the Ph.D., defense and all that stuff. Next month I will be back at work

1) Let's see - ClarkYH and Clark Y: Since the Clark Y has a bit more camber than the Clark YH, and also a higher Cl_max, this should give you aerodynamic twist (washout), and a delayed tip stall. The model should fly fine if you stick with your original plan. However, the real LaGG-3 used a different airfoil: NACA 23016 at the root and NACA 23010 at the tip, if my info is correct. All these airfoils will do ok at model Reynolds numbers, but if you want to use the scale airfoils instead of the Clark Y and Clark YH like you planned, then I would add some geometric washout since those two NACA airfoils have the same amount of camber.

2) Incidence depends on the "sit" that you want for the model in the air (nose high or nose low). If you go with the Clark airfoils, then you will use a bit more camber than the original used, so the model may tend to fly with the nose slightly low, especially at high speed. So, I would place the wing at a slightly lower incidence than on the full-scale, although I wouldn't go below zero incidence. On the other hand, you might not even notice the difference. The original incidence is a pretty good place to start.

3) Thrust lines are difficult to predict in advance. Many models get away with zero down and side thrust. A couple of degrees down and maybe a degree or so side-thrust may be a good idea, but that is just purely based on past experience. Compare it to what you used on your Yak - if you had no trim problems with the Yak, the setup should work fairly well on the LaGG also.

Cheers,
Bennie

yee-ha

Anything new going on here? I am hoping this project is a great success..............and that you will sell me one.

mihaj

Sorry guys,
I've being busy lately and I don't have much to show.
I was mostly working on details. Hopefully we'll start cutting parts for first prototype in two weeks.
Here is fuselage with lightening holes and tail wheel retract installation.

Cheers
Mike

mihaj

Hi group,

Finally I'm back with some updates.
I started to generate 2D parts from my 3D model. Here are fuselage formers that are ready to be cut. Since there are so many of them (there is still one missing, it's waiting for wing pins to be placed), majority will be cut out of 1/8 balsa.
Now, I need your feedback here. I'm planning to split some of the balsa formers into three, four or five pieces and have the pieces cut with grains going along ways. This should increase structural strength of balsa former without adding weight and off course it will make the building process longer (may be one extra day). Any thoughts?


Regards
Mike

Kmot

My Feedback: (24)

Looks like this is really going to be a builders kit!

Chad Veich

My Feedback: (60)

Mike, I think that splitting the formers into multiple pieces to take advantage of the grain is a fine idea. With laser cutting,the parts could be designed to interlock which should reduce construction time. I'd rather build the formers up than have to add a crossmember to the formers to stiffen them. Just my .02 cents.

mihaj

Hi There!
Yep, it will be a little bit more complicated than Yak-3. But, I don't think it will be more difficult to build.

Mike

mihaj

Thanks Chad,

I sure will have interlocks on every part.

Mike

mihaj

Hi,

I'd like to apologize for not posting a progress updates. I'm still working on this project. At the moment I'm preparing 2D parts for CNC. This is very boring process of generating outlines from 3D model, clean-up and verification of lines and line types.
Yesterday, I was "fitting" center of the wing to the fuselage. Finalized position, added 1 degree of incidence and positioned wing dowels and wing bolt plates.
Servo tray will be designed and positioned during first prototype build to help with balancing.

Stay tuned.
Regards
Mike

mihaj

Hi group,

Just want to keep the thread going.
Here is aileron servo placement.


Cheers
Mike

mihaj

Here is a wing pin and flap servo placement.
Gold'n'Rod will be used to drive flaps.

Mike

Connery

What CAD program are you using?

mihaj

I'm using Cobalt. It is an Ashlar-Vellum product.


Mike

Connery

Nice looking product. Sure looks like is makes it easy to lay out everything. Very impressed with your work.

mihaj

Thanks for kind fords.

Mike

jcflysrc

My Feedback: (50)

Very nice work indeed.

Jim

mihaj

Hi there!

Here is a test fit of wing to the fuselage.



Mike