Chris McG F-86 Sabre Dog build blog

[McG 6969]

Hello again,

In relation with the building board and the jig, I forgot to mention some ply ‘bridges’ - with a scrap bit of balsa underneath - that I added at the outside of both R13A's.

They allow for an easy clamping of the wing jig to the board.

Of course, it’s not the wheel, aspirin or bakelite invention, but I thought it could help some other newbies like me…

Hakuna matata

Chris

BRU - BE / CTR Jig Stuff #4 Control

[McG 6969]

Hi everybody,

As I don’t have some pics of the cut wing sheets parts, what about some news of the BAF’s Aerobatic Team >

The ‘Red Devils’ story

(maybe a bit boring for some of you, but you can always skip reading the following posts) …

Early 1957, under the impulse of Maj. Robert "Bobby" Bladt a demonstration team is created. At that moment, the team was flying the Hawker Hunter based at the 7th Fighter Wing of Chièvres Airbase. It was composed of instructors of the "Ecole de Pilotage Avancée" (EPA), entered multiple international airshows in Europe and got rapidly an established notoriety.

During the summer of 1958 - the year of the World Expo in Brussels - Bierset Airbase is organizing one of the largest events ever in Belgium, the ‘Nations Meeting’. With the presence of the French, British, Italian, Portuguese, Greek but also the US Navy and the USAF demo teams, it becomes a huge success in presence of the Belgian King and more than hundred thousand visitors.

The Belgian demo team is more than up to its task but one detail gets ‘ennoying’. All the demo teams are wearing fancy colours, great deco schemes and smoke generators while the Belgians still have the Sq.7 camo paint (cfr. pictures shown).

(to be continued)

Hakuna matata

Chris

BRU - BE / CTR Red Devils Control

[McG 6969]

Hi there,

Here we are again,

The ‘Red Devils’ story

(part 2)

It would be a good thing to have a colourful deco scheme for the Hunters but Lt. Col. De Bueger, Chièvres’s Airbase Commander, doesn’t really fancy that idea.

A few months later, a few days before the 19th display of the SBAC (Society of British Aircraft Constructors) at Farnborough (UK), Bobby Bladt decides to paint the bottom of the wings of four Hunters in the Belgian colours as per the idea of the ‘Patrouille de France’.

 

The day following the show, Bladt will be severely ‘blamed’ by his Airbase Commander for his initiative…

But in march 1959, Lt. Col. Jules Kaisin takes over the command of Chièvres Airbase... and we first see our full national colours applied to the five Hawkers of the demo team. The ‘Red Devils’ become officially recognized…

(to be continued)

Hakuna matata

Chris

BRU - BE / CTR Red Devils #2 Control

 

 

Edited By McG 6969 on 15/11/2019 22:20:31

[dirk tinck]

Hi Chris,sorry i didn't respond to you questions but i was doing other ''stuff' 'than modelling for the last days.

I saw most sabre builders glued the wing jig together but i just pinned it down to the plan without glue .This way i can take it apart after the build. Made up the wing skins a little to big and now i'm waiting for my spars.

In the meamtime started the fuse, will post soon.

[McG 6969]

Thanks for your visit and comment, Dirk.

In fact at the moment, I'm spending more time reading the different blogs than at actually building.

And I still have a lot of question marks as to 'how to'...

I glued my jig together as it seemed easier to remove from the board when needed.

I could 'stain & wax' it later on, take it with me to Conwy and sell it to Drew Pritchard as he's very keen on 'industrial miniatures'...

I also made the wing sheeting about 10mm larger at the LE, tips and TE with only the roots remaining 'flush'.

I'm going to use hard balsa spars. Are you too or using a spruce substitution?

Cheers

Chris

ps > ... don't forget to add the 1,5mm balsa strip on top of both R1's...

[McG 6969]

Hello again,

I'm afraid the Brazilian GP held me away from La Grotte and from bashing balsa this weekend, but at least it helped to offer you the next part of...

The ‘Red Devils’ story

(part 3)

In September 1960, Robert Bladt is promoted to the BAF HQs and the ‘Bladt’ era seems over but Cpt. Yvan Deprins, his most experienced wingman and friend, takes over his leading task.

He will lead the formation of the 4 red Hunters during 3 years with more than 30 exhibitions.

Their very last appearance will be during the official retirement ceremony of the Hawker Hunter on Friday 4 October 1963 at the 7^th Fighter Wing of Chièvres Airbase.

With his team disbanded, Capt. Deprins decides to prepare the ‘promotion’ of the future return of the Red Devils by working on the deco scheme of the successor. His idea is to decorate an aircraft and use it for display at future national events or open-doors. He promptly receives the benediction of Bobby Bladt at the HQ plus the support of his Base Commander at the 7^th Wing.

(to be continued)

Hakuna matata

Chris

BRU - BE / CTR Red Devils #3 Control

[McG 6969]

Hello to all (still there),

The ‘Red Devils’ story

(part 4)

But as this project remains ‘non official’, no real budget is available and he as to find a modern looking subject at nearly no cost.

The answer will come from his friends at the Dutch Koninklijke Luchtmacht and in particular the display team of Sq.700 and Sq.701.

Two F-86K-17-NF of the same type were ‘obtained’ - at the cost of transportation - for the project: Q-259 (reg. 54-1259 / 213-29) retired from duty medio ’63 & Q-273 (reg. 54-1273 / 213-43) scrapped in ’62 after an emergency landing in Kamp Zeist but complete and perfect as a spare parts bank.

 

Q-259 on its way to Chièvres Airbase to be reassembled and restored to its original - hopefully airworthy - condition by the groundcrew and fitters of the 7th Wing… (end, finally)

Now at least you all know why I’ve decided to have a Sabre Dog as my PSSA MB…

Hakuna matata

Chris

BRU - BE / CTR Red Devils #4 Control

Edited By McG 6969 on 18/11/2019 19:05:51

[Harry Twist]

Hi Chris, thanks for sharing the Red Devils story. The Hawker Hunter always looks good in red!

 

Edited By Harry Twist on 18/11/2019 19:15:51

[McG 6969]

Thanks Harry.

Yes indeed, regarding the Hunter outfit. There is a - splendidly restored - red 'speed record' Hunter in an Airfield Museum in UK (Tangmere, possibly?).

Cheers

Chris

[McG 6969]

Hello to all,

I just hope the majority of the visitors survived my RedDevils’s story, but let’s stop that historical proza - which is not that evident in a non-native language - and start some balsa bashing.

As my bottom wing sheeting was now good to go, I started drawing the different lines needed.

After completion, I could present the spars - hard balsa - and glue them w/ Aliphatic to the sheeting.

As Phil C suggested, I oversized my wing sheeting and it seems easier later to handle the gluing of the LE & TE with a bit of margin. Easily cut away after the wing half is completed.

Following the suggestion of Harry T and Simon W2, I also made the top sheetings and these are 'stored' away safely with the hope to be able to find them back when needed...

Hakuna matata

Chris

BRU - BE / CTR Starboard Wing Control

[McG 6969]

Hi again,

As I only had a short session at La Grotte, I decided to leave the wing halves alone and to prepare some other bits.

Both WP1 are not entirely conform to the side view plan where they seem to meet the former behind them.

I decided to modify them slightly - cutting off about 5mm and gluing it back at the other side - so they could but against the former (F7?) later. The final adjusting will be done when getting the fuse halves together.

The battery box was a pleasure to assemble - thanks Martin - and I decided to make it a bit lighter as my ‘longer’ Dog fuselage will gain some weight anyhow. I only drilled a few holes in the ‘side’ parts.

QUESTION please, gents > do PSS aircraft generally need some extra weight at the front and is it necessary to foresee some ‘lead’ box there?

Hakuna matata

Chris

BRU - BE / CTR Bits Control

[Martin Gay]

Chris,

The prototype Sabre now has the CG at 172mm back from F4 (was 165mm on the plan). This is acheived with 110g of lead in the battery box front of the 4 cell Nimh battery.

You may not need any lead in your longer version.

Martin.

[McG 6969]

Thank you for your fast reply, Martin.

With the Dog, I could even bring the balance weight closer to the radome nose, allowing for some weight reduction.

Now you mention "4 cell Nimh battery" and I thought about using a 2S Lipo w/ UBEC to feed the RX...

I suppose one of the reasons being that the Nimh pack can be charged in situ, but then I need some switch and charge socket on board, do I?

Can someone please bring me some light in the newbie- tunnel with the specs of the electrical bits & pieces I need for the Sabre build. Thanks in advance.

If I can order them from HK, it should be a lot easier/cheaper to get those to BE.

Cheers

Chris

[Andy Meade]

If you want to avoid the use of a nimh battery, I'd recommend a 2 cell LiFe. All my fleet now use these, and are perfectly safe to charge in the aircraft. What's more you don't need a UBEC (potential failure point) as they are 6.6v nominal.

[Martin Gay]

Most modern (2.4GHz) receivers can handle higher voltages, my Jeti ones can go to 8.4v.

Just make sure your servos will handle more than 6v. Some can't, so make sure to check the specs!

[McG 6969]

Thank you both for your info, gents.

When looking for a battery, should 1500 > 2000 mAh be OK? And where to order one (Zippy/HK?).

I still need to find a switch/charging socket device !

Regarding the LiFe voltage of 6,6V, my projected X8R receiver can handle up to 10V, so no worries there.

But I'm planning to use analog Corona 929MG or digital 939MG servos and I can't find their maximum voltage spec...

@ Martin > can your TGY-9018MG servos handle 6,6V ? ...

Thanks in advance for your guidance.

Cheers

Chris

[Martin Gay]

Chris,

The Hobby King website lists all three servos as 4.8V / 6.0V, so they are probably not able to handle 6.6V.

The Corona DS939HV, from Hobby King is rated for 6.0V / 7.2V though.

**LINK**

[McG 6969]

Thank you for the link, Martin.

I saw those Corona HV servos but didn't pay enough attention to them.

Now the jury is still out there...

But, as your battery box's internal dimensions are 42 x 42mm and the LiFe 6,6V are larger, I guess I'll stick to a 4,8 or better a 6V Nimh receiver pack, enabling me to use the Coronas or your TGYs.

Could you please tell me what you're using regarding battery & switch/ charge socket. I mean brand, specs and where to get them...

Thanks in advance & cheers

Chris

 

Edited By McG 6969 on 21/11/2019 18:06:24

[Chris Barlow]

Chris

I tend to use 4.8v 2000mah NiMh packs for PSS simply because they usually last for a full days flying and add sufficient weight where it's usually needed. On some models I have a 4.8v sub c size 3300mah for extra nose weight!

The LiFe batteries are good at delivering a consistent voltage but will drop off rapidly when exhausted (and may even be damaged) The NiMh will drop off gradually and an X8R won't be affected too much. You'll notice the servos starting to slow if you let the battery drain too much but you'll still have control to bring the model in safely.

Remember though 4.8v NiMh is a 4 cell pack but 6v NiMh is a 5 cell pack and won't fit in the battery box.

[McG 6969]

Thank you for your kind advices, Chris.

I guess I'll keep it simple (& cheap...) and go for the Nimh solution.

The 4 cell 4,8V (in two rows) would be perfect for the battery box but I think a 5 cell 6V version in two rows as well (3 + 2 on top), could also fit the box if they are slightly 'tilted' in diagonal. I'll have to check that before committing.

Any additional guidance is always welcome of course...

Cheers

Chris

[Chris Barlow]

If you want to experiment you can tape some simple AA size batteries together to see what fits.

[McG 6969]

That's exactly what I had in mind, Chris.

I'm having a session at La Grotte this afternoon, so we'll rapidly have the answer, I guess.

Thanks again for your assistance.

Cheers

Chris

[John H. Rood]

Captain Barlow, your happiness with the 4.8V NiMH route is glad news for me -- as 4.8V NiMH is really the only thing I know how to use nowadays -- so seeing as it works for you, I believe I can just stay lazy oops I mean "keep it simple"!

Cadet McG, kudos on your fine workmanship and meticulous ways thus far.

"Now GO, and commit this sin no more."  

 

Edited By John H. Rood on 22/11/2019 16:44:09

[McG 6969]

Hello to all,

Following Chris B’s advice, I made up a pack of 4 AAs in two rows and obviously they fitted the battery box easily.

Next was to try a 5 AAs combo (3+2 on top) and they will fit provided they’re a bit lifted on one side. So we have the choice of 4,8 or 6V. I will post some pics later.

I started making a rib sanding jig to have some ‘repeatable’ progress with the ribs.

The ply I used is from a Spanish ‘mandarines’ (tangerines) tray and is totally ‘junk’ material, but at least the fruit was delicious.

As I will be using some paper tubes for the servo wires, I had to foresee some holes in R2 up to R9. This makes the process quite a bit slower especially because the swept angle dictated some bevel sanding. Only about half a dozen ribs finalized so far.

Thanks to my “note to self”, at least I didn’t forget to add the bit of balsa strip above the wing jig R1s. The little ‘deviation’ of the red line is purely due to my mid-finger being a bit to long…

Hakuna matata

Chris

BRU - BE / CTR Nimh Control

ps > this Cadet will very probably have a lot more sins to hide, John… but thx.

[McG 6969]

Hi again,

As promised, here are some pics of the Nihm test.

Two rows of 2 AA batteries are obviously not a problem at all.

A 3+2 combo is a touch to wide at 12,5mm each, plus taking in consideration that there will be some heat shrinking ‘envelop’ around them.

However, if slightly ‘tilted’, it becomes easy enough to get them in without binding.

Some plan is to foresee a Depron ‘wedge’ to slide the pack maximum forward.

I guess this is quite workable?

Hakuna matata

Chris

BRU - BE / CTR Depron Wedge Control