A Different F-13 : The Junkers Larsen JL-6

[Tweener]

For some time now, I have been interested in building the little known American built version of the great Junkers F-13, the Junkers Larsen JL-6. While only a half dozen or so were built, 3 of them were used by the U.S. Navy for tests in the early 1920's.

 

A quick stop into a model shop on the way home from college netted a copy of the Revell F-13 kit at a very nice price ($20) compared to what I had generally seen online (In the range of $30 - $50), as well as a number of other kits, including 2 SH Nomads, A Testors SNJ (Which will become an A-27), a 4th Revell P-26, and a Heller Dominie (which will also be finished in American markings, more on that later).

 

 Thankfully, the Revell kit really is a little gem, with full engine (Which can be displayed by cutting off and reposing the top engine cover along a provided line), interior, option of floats or wheels, and in my boxing, 4 decal options. covering German, Swiss, and Free City of Danzig markings. While I imagine that the U.S. Navy versions probably differed from standard F-13s in regards to the interior, I don't care much to change what is provided, even if I had reference. (On a side note, reference material, or at least photo's, do seem to be rather widely available, something I had not initially expected. 

 

However, there is one issue - the trademark JL-6 inscription on the right side of the nose, and the JL logo marked on both sides of the rear fuselage. Both are shown in the photos below.. Does anyone know where I might be able to get these made as decals? Perhaps Mark at Starfighter Decals would be interested?

 

 

 

 

 

That's all for now.

 

Thanks, Tweener

Edited August 11, 2018 by Tweener

[Tweener]

First Update:

 

Building has not yet begun as research is still underway. So far, I have noticed a few major things that will need correcting.

 

The biggest of these is to correct the shape of the ailerons. The Revell kit offers the more common longer wing and straight ailerons, while the JL-6 was built with the earlier style shorter wings with curved ailerons. This can be (partially) fixed with a Master X resin set (curved ailerons), which, naturally, costs more than the original kit.

 

Second, it appears as though most of the 8 (or possibly 25) JL-6s produced featured the earlier, smaller rudder, but the rudder in the kit is the later, larger style.  2 photos show the later style rudder on JL-6 airframes, one on wheels and one on floats. If I'm daring, I might just go for floats. 

 

Third is the shape of the bulge on the right side of the engine as seen in the photo above. It doesn't match the shape seen on the kit plastic. This may well have to be ignored as I can't think of any way to correct it without damaging the surrounding corrugations. Advice is welcome.

 

Finally, going back to the wings, we find our last (possible) issue - their length. There were at least 2 different wing sizes used on F-13s, and it is my assumption that the shorter style of wing would have been used on the JL-6 series given that they were equipped with the aforementioned curved ailerons associated with the shorter wing type. This is supported by the fact that, technically, the JL-6s were the first produced F-13s. If this is the case, I will be unable to produce a JL-6 as I am all too happy not to try and correct the size of the wing. If I am going to do that, I'll scratchbuild a Fokker C-14...

 

Once building begins, I will of course create a different thread in the WIP section. For now, I figured it would be worth leaving my ponderings and notes here on the unlikely chance that someone else has ever head of the JL-6 or wants to build one.

 

That's all for now.

 

Thanks, Tweener

 

 

Edited August 14, 2018 by Tweener
Roger provided new info on wing and aileron type.

[VH-USB]

On ‎8‎/‎11‎/‎2018 at 2:53 PM, Tweener said:

However, there is one issue - the trademark JL-6 inscription on the right side of the nose, and the JL logo marked on both sides of the rear fuselage. Both are shown in the photos below.. Does anyone know where I might be able to get these made as decals? 

Thanks, Tweener

I'd suggest you contact Mika at Arctic Decals.

He does fabulous work and can easily do small, custom decal orders. He'll create your needed art as well.

Highly recommended!

[Roger Holden]

2 hours ago, Tweener said:

 

The biggest of these is to correct the shape of the ailerons. The Revell kit offers the less common longer wing with straight ailerons, while most F-13s were equipped with shorter wings with curved ailerons. This can be (partially) fixed with a Master X resin set (curved ailerons), which, naturally, costs more than the original kit.

 

Second, it appears as though most of the 8 (or possibly 25) JL-6s produced featured the earlier, smaller rudder, but the rudder in the kit is the later, larger style.  2 photos show the later style rudder on JL-6 airframes, one on wheels and one on floats. If I'm daring, I might just go for floats. 

 

Finally, going back to the wings, we find our last (possible) issue - their length. There were at least 2 different wing sizes used on F-13s, and it is my assumption that the shorter style of wing would have been used on the JL-6 series given that they were equipped with the aforementioned curved ailerons associated with the shorter wing type. This is supported by the fact that, technically, the JL-6s were the first produced F-13s. If this is the case, I will be unable to produce a JL-6 as I am all too happy not to try and correct the size of the wing. If I am going to do that, I'll scratchbuild a Fokker C-14...

 

 

The JL-6s were equivalent to the very first German F-13s built and had the original short wing, with curved ailerons. Very soon, the span was increased to produce a longer wing (also with curved ailerons), which the vast majority of F-13s had.  (This was retro-fitted to most, if not all German built F-13s, leaving the US JL-6s as the only planes to see much service with the short wing....) But this long wing also had early and late versions. Unfortunately, Revell copied a museum aircraft built from several wrecks, which has an early fuselage mated to a late wing (from a very late aircraft which also had a longer fuselage and 'square' fin.rudder,plus those near-parallel ailerons. This late wing also has much wider joint straps covering the centre-section to outer panel joints than the early aircraft had.  So building an accurate early-ish F-13 from the kit needs a lot of work.)

 

But the early JL-6 span change is quite easy as it  just involves hacking off the wing tips and producing a new tip enclosure. Rest of the geometry is the same. Not sure about the aileron length.

 

20-odd JL-6s were produced. The most well-known were the 2 aircraft used by Imperial Oil for prospecting in Canada and the US Postal Service aircraft.

[Tweener]

2 hours ago, Roger Holden said:

The JL-6s were equivalent to the very first German F-13s built and had the original short wing, with curved ailerons. Very soon, the span was increased to produce a longer wing (also with curved ailerons), which the vast majority of F-13s had.  (This was retro-fitted to most, if not all German built F-13s, leaving the US JL-6s as the only planes to see much service with the short wing....) But this long wing also had early and late versions. Unfortunately, Revell copied a museum aircraft built from several wrecks, which has an early fuselage mated to a late wing (from a very late aircraft which also had a longer fuselage and 'square' fin.rudder,plus those near-parallel ailerons. This late wing also has much wider joint straps covering the centre-section to outer panel joints than the early aircraft had.  So building an accurate early-ish F-13 from the kit needs a lot of work.)

 

But the early JL-6 span change is quite easy as it  just involves hacking off the wing tips and producing a new tip enclosure. Rest of the geometry is the same. Not sure about the aileron length.

 

20-odd JL-6s were produced. The most well-known were the 2 aircraft used by Imperial Oil for prospecting in Canada and the US Postal Service aircraft.

What do you mean by early fuselage or longer fuselage? I have yet to find anything about fuselage changes. Now I'm praying that I don't have to change the fuselage length as well...

 

As for the wing, do you know how much I would have to cut off? If it isn't much I may give it a try. One thing that I have realized, however, is that ultimately I would have to choose between correct ailerons and correct wing length... otherwise I would have to build a whole new wing.

 

My absolute backup plan is to cut off the nose and replace it with a radial engine, as was seen on some FInnish birds. I suppose if I were to do that, though, I might as well commit to the JL-6... 

Edited August 14, 2018 by Tweener

[Roger Holden]

11 hours ago, Tweener said:

What do you mean by early fuselage or longer fuselage? I have yet to find anything about fuselage changes. Now I'm praying that I don't have to change the fuselage length as well...

 

As for the wing, do you know how much I would have to cut off? If it isn't much I may give it a try. One thing that I have realized, however, is that ultimately I would have to choose between correct ailerons and correct wing length... otherwise I would have to build a whole new wing.

 

My absolute backup plan is to cut off the nose and replace it with a radial engine, as was seen on some FInnish birds. I suppose if I were to do that, though, I might as well commit to the JL-6... 

The longer fuselage is only on late aircraft (circa 1928-32), so shouldn't concern you too much (unless you plan to build one to go with the appropriate wing provided in the Revell kit). D-2313 seen here has the long fuselage :

https://www.junkers.de/flugzeuge/specials/f13

 

The JL6 has a 48' 7'' wingspan (205.6 mm in 1/72), vs 58' (245.5 mm) in the Revell kit, so around 20 mm has to be removed from each wing tip.  I think the inboard end of the aileron was in the same place, so the ailerons just got extended too.

[dogsbody]

I have this resin set that I bought a few years ago. I know that right now they are out of stock, but maybe EBay might have it.

 

 

 

Chris

[wrx15]

Was just searching on the Junkers Larson aircraft the other day then  in a separate search saw your post.  Interesting coincidence. I think.  Did not rellize they were made in the USA and used by USAAC.

 

Just got an F-13 on ebay for a similar price.   Usually they go for quite a bit.  I also have the pigeon carrier version.  Imagine cleaning that in real life.  

https://www.scalemates.com/kits/963566-l-demann-modellbau-junkers-f-13

 Look forward to seeing your build.

[Tweener]

On 8/14/2018 at 9:59 AM, Roger Holden said:

The longer fuselage is only on late aircraft (circa 1928-32), so shouldn't concern you too much (unless you plan to build one to go with the appropriate wing provided in the Revell kit). D-2313 seen here has the long fuselage :

https://www.junkers.de/flugzeuge/specials/f13

 

The JL6 has a 48' 7'' wingspan (205.6 mm in 1/72), vs 58' (245.5 mm) in the Revell kit, so around 20 mm has to be removed from each wing tip.  I think the inboard end of the aileron was in the same place, so the ailerons just got extended too.

I remember reading on a review of a correction set for the F13 that the inboard end of the aileron was about 3mms off, but that isn't enough to concern me. I think what I will do is buy the correction set and just cut down the wing and ailerons for as much of the 20mms as still looks reasonable. Thanks for the measurements!

 

On 8/14/2018 at 4:05 PM, wrx15 said:

Was just searching on the Junkers Larson aircraft the other day then  in a separate search saw your post.  Interesting coincidence. I think.  Did not rellize they were made in the USA and used by USAAC.

 

Just got an F-13 on ebay for a similar price.   Usually they go for quite a bit.  I also have the pigeon carrier version.  Imagine cleaning that in real life.  

https://www.scalemates.com/kits/963566-l-demann-modellbau-junkers-f-13

 Look forward to seeing your build.

I had been looking at that kit of the pidgeon carrier version recently myself, cleaning one out is a job I would be quite happy to pass on. A very neat concept however.

 

On 8/14/2018 at 12:13 PM, dogsbody said:

I have this resin set that I bought a few years ago. I know that right now they are out of stock, but maybe EBay might have it.

 

 

 

Chris

That is the set I have been looking at, it was previously released  by Master X if I recall correctly. Shame it costs more than the actual kit, but if it's the cost of accuracy so be it. I just want to know why there is a replacement fuselage roof? Was it because of a different engine type or is that another problem with the Revell kit?

 

Thanks all, Tweener

[dogsbody]

1 hour ago, Tweener said:

I remember reading on a review of a correction set for the F13 that the inboard end of the aileron was about 3mms off, but that isn't enough to concern me. I think what I will do is buy the correction set and just cut down the wing and ailerons for as much of the 20mms as still looks reasonable. Thanks for the measurements!

 

I had been looking at that kit of the pidgeon carrier version recently myself, cleaning one out is a job I would be quite happy to pass on. A very neat concept however.

 

That is the set I have been looking at, it was previously released  by Master X if I recall correctly. Shame it costs more than the actual kit, but if it's the cost of accuracy so be it. I just want to know why there is a replacement fuselage roof? Was it because of a different engine type or is that another problem with the Revell kit?

 

Thanks all, Tweener

The only visible difference between the two is the hole in the top of the Revell roof for the exhaust pipe. The resin kit has the pipe coming out the right side of the engine cowling and running down the side of the fuselage. Other than that, they are identical.

 

This is the only one that Master X has available right now: http://www.master-x.wz.cz/F13eurasia.html

 

 

Chris