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Focke Wolf Ta 154 Laser

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Chris Walby31/03/2020 19:50:01
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1198 forum posts
299 photos

ta 154.jpgIn Feb2019 having flown my Laser powered Seagull Mosquito I hatched a plan to obtain the other Moskito.

This one was not going to be quite as easy as buying and modifying an ARTF, but how hard could it be?

Tom Gaskin 131/03/2020 20:28:22
36 forum posts
5 photos

Outerzone have a nice sized plan for one of these

Tom

Chris Walby31/03/2020 20:52:29
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1198 forum posts
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A bit of history

Apparently the Germans were very impressed with the DH Mosquito in its role as pathfinder and photo reconnaissance and especially with its use of non metal airframe. Kurt Tank of Focke Wolf had already been designing aircraft using wood composites and here was an opportunity to submit a design for a twin engine night fighter with a similar performance as the Mosquito.

Despite having the same wingspan and composite wood air frane the Ta154 differed in being high wing and fuel tanks within the fuselage. This allowed for a thinner wing section and less likely to be damaged under fire.

Major problems arose when their only Tego film (glue) factory was bombed and an alterative less strong glue was used. Worse than that they later found after a number of wing failures that the glue was corrosive to the airframe.

Back to my Ta 154

Plans for 70 inch version were obtained (if only I had looked in Outerzone!) but not to worry at least I has a hard copy to look and measure over.

Looking at the wing area and target weight it soon became apparent that a 70 inch version with twin Laser 70 in it was going to have a high wing loading.

The answer was to copy the Mosquito and go for 80 inch wingspan which brought me to the U/C. The original plan had fixed and while in the 70's/80's there was no real economic alternative I thought it could not be too difficult to do.

Chris Walby31/03/2020 21:07:26
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1198 forum posts
299 photos

I'll be compressing the last 12 months into hopefully what would appear to the reader quite a quick build although rest assured its been very time consuming and its not finished yet!

Lets start with the airframe, apologies to the trad builders, but I don't think I am going to live long enough to cut wing ribs and bulkhead by hand so it was off to see Chris at SLEC

No problem with increasing the wingspan from 70 to 80 inch, help in selecting wood sizes and a set of nacelle parts to assist with engine and U/C design.

20190517_133949.jpg

Now the first issue was that the Laser 70 engine sits on engine mounts and the bulkheads are in the wrong place. Good news the was to use the beech bearers for the U/C, but getting the U/C to retract into the nacelle was going to be a challenge.

20190526_205847.jpgPS Not engine or tank final position!

Edited By Chris Walby on 31/03/2020 21:10:10

SR 7131/03/2020 22:21:58
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432 forum posts
138 photos

Following Chris, i do like builds with a difference

Ace01/04/2020 09:22:24
304 forum posts
17 photos

Watching with great interest as I do love a good twin especially with proper engines wink

Cliff Bastow01/04/2020 09:43:35
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884 forum posts
454 photos

Nice plane Chris,

I built a small electric one from the Tony Nijhus plan,

It was a nice flier and looked great in the sky.

Good luck with the build.

p5012164.jpg

Nigel R01/04/2020 09:47:51
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3741 forum posts
585 photos

Nice - following yes

Cliff Bastow01/04/2020 09:47:59
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884 forum posts
454 photos

p5102174.jpgp5102175.jpg

Martin Harris01/04/2020 13:01:12
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9262 forum posts
245 photos
Posted by Chris Walby on 31/03/2020 21:07:26:

20190526_205847.jpgPS Not engine or tank final position!

What's the story with the engine mounting bolts, Chris? Is there some sort of flexible mounting going on?

Chris Walby01/04/2020 14:40:45
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1198 forum posts
299 photos

Cliff, I built a TN Moskito but In kept breaking motor bulkheads and cowls every time I landed and in the end resorted to folding props and reduced performance as you don't have the same choice as standard props.

I tried differential throttle control as mine did not have a rudder servo - very weird yaw and un-scale like + I found that colour scheme almost impossible to see with a winter sky against trees (funny that!). After about 4 major rebuilds due to crash damage it ended its live with a 50ft lawn dart (not fully explained but either RX or ESC failure - money is the ESC and at low speed, low altitude and no rudder not catchable).

Martin - I am at a total loss as to your comment as the photo clearly shows the manufacturers supplied engine bolts with rare spacers + recommended Nylon engine mount and ply bulkhead. This was the prototype bulkhead and the final supplied by SLEC has the beech bearers (photos will be published in due course) oh and the engine rotated 90 degrees for carb/tank level.

I'll post progress shortly and thanks to all that are following.

Martin Harris01/04/2020 15:24:47
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9262 forum posts
245 photos

It was those "rare spacers" that I was wondering about - what's their function?

Chris Walby01/04/2020 15:46:45
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1198 forum posts
299 photos

Martin - Did Jon not give you a set...strange surprise, mind you he did he didn't give me a set with the last engine either crying

Jon might know what there true purpose is, but being a new boy I just thought they were spacers so the socket to nut does not foul the side of the engine bearer + they look nice.

PS - I think washers fowl as their OD is greater than the nut across corners diameter.

Jon - Laser Engines01/04/2020 16:00:28
5422 forum posts
263 photos

Spacers eh..

Well to be fair they are spacers technically and they are intended to be used on the 120 head bolts as 40mm bolts are too short, and 45mm bolts are too long. But, fit a 3mm spacer on a 45mm bolt and its all good. We could change the head design, but then the bolts on the 150/155, 300, 180 and 360 would be wrong.

Anyway, many of our customers complained they were unable to get 4mm washers that sat nicely on the mounting lug so i used my already existing spacers. They are little thick as washers go, but as it meant i didnt have to make another part i went for it.

Chris Walby01/04/2020 20:57:55
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1198 forum posts
299 photos

Moving on the next decision was regarding U/C as the original had fixed, but I though it deserved retracting.

Chat with Dave at Inwoods resulted in a very nice nose wheel oleo and retract, a couple of retracts and some buggy shocks. Mock up resulted in this

 

20190329_185643.jpguc mock up v1.jpg

Now at this point I realised I could make the retracts, but might never get the rest of this project progressed so I started a conversation with Ken King.

I sent some drawings and the mock up and Ken did lots of thinking with the focus on lightweight and simple design.

Really please with the result and can take no credit for Ken's great work. If it flies okay I will add tubes over the rods to make it look a bit more scale.

20191024_105827.jpg

Around this point we spotted the UC is in front of the C of G

Edited By Chris Walby on 01/04/2020 20:59:21

Chris Walby04/04/2020 10:23:11
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1198 forum posts
299 photos

Well I guess its time to mention the Lasers, the idea was that I would cut my teeth with a pair of 70's in the Dual Ace and then put them in the SG Mosquito. Great plan, but then I started pining for the Dual Ace and and was lucky enough to pick a second matched pair for it. As the days worn on I started thinking about a plan/scratch built twin and use the Dual Ace engines again.

Of course it would take months to build the Ta 154 and if it all went pear shaped with the Ta 154, then the engines could no back in the Dual Ace

Jon kindly loaned me a runway darted engine after I spent considerable time with my spare 80 lining up the bulkhead and everything else to then realise that the 70 and 80 are different in almost every dimension! Doh. More discussions and progress with Chris at SLEC and the ribs/bulkheads were coming along nicely.

Roy at SLEC had selected some suitable wood for the canopy plug and after lots of hacking I had what I thought would be suitable. Then a bit of too and throw with test pieces Roy arrived with a very nice canopy.

20200404_091144.jpg

Next time....the collection of the wood pack

Chris Walby13/04/2020 06:55:02
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1198 forum posts
299 photos

With a early morning drive up to SLEC, friendly chat with the office staff and then around to see Chris for the wood pack and drawings. While there I though a few other bits and tools would be in order and then back home - via Inwoods. (time to talk pilots).

Well I must say the dry fit of the wing with the additional removable sections was a real pleasure after a bit of giggling with the wing tube (my doing).

20190923_130027.jpg

Next time

Nacelles and fuselage

okay quick taster...

20190916_133120.jpg

Edited By Chris Walby on 13/04/2020 07:04:39

Martin Harris13/04/2020 12:46:48
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9262 forum posts
245 photos

To anyone reading this blog and wondering about quick trips to SLEC in the present climate, it might be worth pointing out that Chris stated at the beginning that he was compressing the last 12 months work into this thread.

alan p13/04/2020 19:07:28
257 forum posts
7 photos

Must admit I was hoping for enlightenmentthumbs up

Chris Walby18/04/2020 22:36:26
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1198 forum posts
299 photos

Now where was I, oh yes nacelles and engines. Well after the self induced cock up with using the spare 80 only to find out almost every dimension was different to a 70 and Jon coming to the rescue with a dummy one for me. It was full speed (at a snails pace) with assembling the laser cut parts.

Its worth mentioning that the original was intended to have twin .40 2 strokes so increasing the wingspan to 80 inch and putting a couple of Laser 70's seemed like a good idea. The design used two beach bearers to support the vertically mounted engines and form the platform for the U/C and I thought it was the best way forwards to be retained. The bearers would finish in the ply bulkheads that the standard nylon engine mounts I use for my engines.

This gave me the flexibility to rotate the engine until the right tank to carb height was achieved. Just as well and mock up had the engine inverted, but once everything was in place side mounted was best.

20191218_181938.jpg

The other advantage is that the beach bearers locate the two ply bulkheads that bolt to the wing. Wing and nacelles assembled separately and fitted together at a later date which I though was a great idea as it allowed be to get the washout and dihedral right without the nacelles getting in the way.

Been a bit demotivated with this recently as it seems to absorb hours for little visual gain, but now I have made progress with the EST I'll get back on this.

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