Gluhareff S-22 - Tuomas

[tuootal]

Bonjour tout le monde!

I have been lurking these build threads for a while and I would like also to contribute something. This forum has been a sort of holy grail of wooden scale glider building and I have been waiting for suitable project to try my wings at this level. I will do my humble attempt of build logging in english, as my french is not good enough despite the fact that I have lived in Paris for an year. Also, you propably cannot understand finnish :).

Everything started in spring when I was browsing and checking some details at J2mcL planeurs. I searched planes designed in Finland where I live. One plane popped up and I thought that there is an error, this is not Finnish plane. Did then some googling and ... yes. It was designed in Finland, but it was so old that it has totally slipped my radar. Design year was 1921.

The story is about two russian emigrants living in Finland who wanted to fly sailplanes. Guy's were brothers, mr. Michael and Sergei Gluhareff. According newspaper article they were supposed to be ex-fighter pilots from Russian air forces (before 1921?!?). They were joined by third guy called Boris Adaridi, Russian descent, but Finnish citizen, son of famous army general.

They designed two sailplanes, M3 and Gluhareff S-22. Where S stands for Soarer. Logically.

Planes flew well, according some comments they made more than 100 flights. I am slightly sceptical as they used catapult to get to air... And they had only small slope (approx. 7-10m).

Nevertheless, planes flew and there are some pictures and even 3-view of S-22 published in book by Adaridi in 1925. Who then moved to France.

Pictures below, including 3-view. These are only existing pictures I have located.

Tuomas

References:
(great many thanks for www.flightforum.fi regulars for assisting me finding details)
http://www.j2mcl-planeurs.net/dbj2mcl/planeurs-machines/planeur-fiche_0int.php?code=2276
http://www.scalesoaring.co.uk/VINTAGE/Books/Langsdorf%20-%20Das%20Segelflugzeug.pdf (page 141)

[tuootal]

I designed this plane to be 1:3 scale with almost all the bells and whistles of original plane. One thing which I skipped (really... yes) was all-wing-flexible (flexible, spring loaded) TE capable moving 75mm up, that was just too extreme.

Anyway, interesting details include:
1. Ailerons are actually moving wingtips.
2. Elevator is all-moving, ie. it is pendel-elevator.
3. Fuselage is extremely short. According interview in Finnish Aero-magazine Gluhareff had concluded that shorter tail contributes to stability. Which is against current wisdom.
4. Ski's, altough I did not draw skis. Anyone can draw skis . There is support for them in place.

I am really, really sceptical whether this plane will be easy to fly. With those jazzy ailerons, large AMT-elevator and incredibly short fuselage it will be really tricky to fly.

But man really needs challenges. This might not fly at all, but I like building.

From aeromodelling perspective this was rather easy design. All structures are quite straightforward. Nothing extremely challenging.

These plans are available for free (yes, free) download at my webpage http://www.iwaru.fi/gluhareff.html

Tuomas

[VincentB]

Hi Tuomas
Whoo, great project, I love the look and ailerons are original I can't wait to see more
Your plans are very beautiful thank's for sharing

[tuootal]

And yes... today I started build.

I will start with elevator.

Tuomas




Everything starts with plans and pile of balsa.




Constructing tip of elevator.




Balsa doublers.







Trailing edge constructed from plywood and balsa.




Tip of elevator tapers agressively







Despite opening in leading edge I will leave this one piece for this phase.




Middle section sheeting and cap strips.

[Christian]

Christian

[michel]

sujet original, bon courage pour la suite .

[Frédéric]

Salut !



Amicalement
Frédéric

[Anonyme]

Magnificent and original project ! Well done Tuomas !!

[tuootal]

Je vous remercie pour vos paroles encouring!

And then to today's dish, fuselage


First keel's and some formers & beginning of box structures


Then more box structures


And finally longerons.


This looks quite strange, like fish :)

Tuomas

[tuootal]

One interesting design element is all moving elevator. I wanted to keep elevator in one piece, just to keep it as light as possible. I ended up with rather interesting structure..


First brass tubes are aligned using plate and retainers. Then it is tack glued to plywood parts.


Now it is ready to be permanently glued.


GF strip, some epoxy


And plenty of compression

Tuomas

[tuootal]

I normally draw interesting and fancy rudder structures and then I build something completely different..





Tuomas

[tuootal]

It's the building day again..

Tuomas
--


Start by adding some planks. I used 2mm balsa with the intent to glass fuz from inside.


I have used table as jig for some time now, and it works rather well. One thing is to remember add secondary 3mm keel parts here.


Wing box parts


Last wing box parts.


Another view. It looks quite complicated, but in real life it is not.


Then to longerons.


Another view.

[tuootal]

This wing has couple interesting features.

First - the airfoil is constantly changing. It starts with HQ 3,5-12 at root, then morphs to HQ 3,5-10 at midsection and then to HQ 3,0-9 at beginning of tip. Tip is almost flat.

Second - those jazzy ailerons...

Tuomas
--


First I have to find all ribs. Some of the markings got lost at cutter and trying to 'feel' correct ribs is ... difficult. Luckily all ribs were present.


All ribs glued to place. Those aluminium bars are just weights to keep everything aligned.


Detail at aileron hinges. I am using brass pipe to align hinge parts.


Finally just an recap of all moving elevator hinge. Looks nice!

[VincentB]

Hi Tuomas,
Nice work How will you make the trailing edge? straight or curve like the photos?

[tuootal]

Hi,

my plan is to make straight trailing edge as in 3-view. But you can see curves in those pictures so if I would be making exact scale plane I would propably do curves.

Incidentally, there are 4 planes which are linked to mr. Adaridi.

M-3 - biplane glider, no plans found, only some really bad pictures. Design by Gluhareff's and mr. Adaridi.

S-22 - this plane. Design by Gluhareff's with 'help from Adaridi'.

Adaridi AD3 - this is actually 'light motorplane', a bit like motorized glider (12hp motor). There are some comments referring to it as having 'similar design' as S-22. Which is true to some extent, but not really. There are similar elements (like ailerons & amt-elevator). But everything else is different (wing platform, fuz, size, ...). Check it here http://www.ilmailumuseo.fi/index.php?page=adaridi . It has been preserved in Finnish aviation museum collection. Bad flier..

And finally fourth one, an plane with no name, so let's call it SK-24.

This SK-24 is extremely interesting as there are no surviving pictures but there is an build log (!!!) of that plane along with rudimentary drawings (!!!!). It was published in periodical magazine 'Suomen Kuvalehti' (SK for short, direct translation is Finnish Picture Magazine) during 1924 as an two part series. They published article describing 'how everyman can build own glider'. In real life two of these were built. Both crashed during maiden takeoff. One was built as an glider which they tried to horse-tow and second was built with motorcycle motor (18hp). There could be long discussion why this plane did not fly, but the drawings are such that I am quite certain that it really cannot fly :). Article has no journalist name, but it says 'that this article is based in explanations and drawings by aeronautical technician B. Adaridi'.

Why is this relevant in this context? Because that article describes how to build trailing edge which gives you identical grooves as in picture and as in Adaridi pictures. Trailing edge is simple 1mm piano wire which has been stiched to canvas covering wings. There is even some detail drawings of airfoils with that structure...

To get exact scale fidelity I could replicate that structure but I think that it is slightly too extreme to my taste. I have seen it couple times done in retroplane build logs, so it is quite doable.

Btw - it could be interesting if you can find some further information of mr. Adaridi's later history. He moved to France after 1925 and I have found some comments that he continued with aviation industry, but what role or what designs I have no clue. Died in Paris 1960.

Tuomas

ps : yes - I did have short building session today, tried to find suitable wing tubes, no luck. Have to go to shop real soon to continue..

[VincentB]

Thank's Tuomas for historic for curiosity, can you post please a view of SK-24
for curve trailing edge, it's very very easy to make with cable, I made that on my Mira and I find the result good and it's very strong

[tuootal]

Most certainly,

I was in progress of getting publication permission from Suomen Kuvalehti as that magazine still is running. It is quite successful and well known magazine here, you can visit their pages here : www.suomenkuvalehti.fi . Today they are totally different style magazine, no more airplane plans...., just weekly politics & business & activities & culture. Rather good, I have had subscription for long time.

I have now obtained permission to post pages to my webpage. Due size constraints I will post here only lowres-version of one page. There is lowres version of whole package (6 pages) in my website http://www.iwaru.fi/gluhareff.html (0.5mb). I did publish also high resolution version at the same location, but... pls. note that it is 43mb... You can find both versions at the bottom of page. Use freely, but whenever referring them you must name source, ie. Suomen Kuvalehti 1924, 1-3.

Great many thanks to Suomen Kuvalehti for granting this possibility!

Couple things worth noting:
1. scans are poor quality. I visited Finnish National Archive to get copies of these pages and the originals were in rather bad shape. This quality also makes files quite large.
2. yes, obviously they are in Finnish :). No translation available.
3. the drawing technique is totally different than the way we do drawings today. They look quite strange, but you propably will understand key idea.

It might be extremely interesting to build actual scale glider based on these plans. It would be tremendous challenge. Where would you hide radio's etc?

Tuomas

[tuootal]

This looks a bit cluttered, but I am using cheap Ikea-shelves as supports to get wing supports aligned. There are quite a lot of gluing going on in this pic. First profile doublers, then lower internal spars, wing tubes, upper internal spars, outer profile-ends etc.


Last tail formers glued in place with elevator horn. I did not glue them in previous phase as now I can get them in level with wings. I had to use epoxy for this joint as the gf does not adhere using PVA-glue.


Torsion sheeting. I am using table & tape to compress torsion LE to place. TE of sheeting is compressed using alu profile. Note that I will glue shear webs in place in next phase as this way saves time on sanding top of shear webs.

Tuomas

[tuootal]

Just testing how the wings sit to fuselage. I really love CAD-designed planes with laser cut parts. Everything fits just perfectly.


Some modelling art, trailing edges glued together


Second wing.


Shear webs to first wing. I am using 2mm shear webs all along. Plywood only at root, bays 1-2.


Then plywood sheeting to wing center part. Quite difficult to get aligned properly. Hopefully it will be good enough.

[tuootal]

Checking fit of wings. Looks good enough.

Tuomas

[tuootal]

Next challenge is to sheet underside of wing shoulder (is it wing armpits? :)) using plywood. Quite easy task, but getting compression done properly required planning.



Before

After

Tuomas

[tuootal]

And here is completed wing armpit. Good enough.




Tuomas

[tuootal]

Bonjour!

I have been doing all kinds of small (and boring) tasks like torsion sheeting, elevator & fuse sanding etc. etc. So nothing too interesting to show, but one thing which is slightly out of ordinary was completed. Elevator linkage. You have to remember that this is all moving elevator so putting linkage outside of elev looks kinda odd. But everything has it's purpose.



Tuomas

[tuootal]

I noticed minor problem with current fuselage structure. This fuselage is a bit like tube with opening for pilot at top. It will be sheeted with balsa. And I used balsa to all longitudial spars.

So all this leads to interesting risk with structure. If there is an knock pushing front of fuselage upwards it will collapse all balsa structures as they are not strong enough. Only longitudial hardwood structure is lower keel. Upper keel is cut due opening for pilot...

This is rather embarrasing.

It means that I must change uppermost spars to spruce. Easier said than done as 6x6mm spruce is not easy to twist around that fuselage shape.



First I must re-connect upper keel just to keep it's shape while adding spruce. The spars which will be replaced are actually already cut short. Cutting was needed to get wing saddle supportd.
Also, I added some missing formers at the same time.


Then spruce spars must be pre-formed using loads of hot water and suitable support. That must dry well.. at least till tomorrow.


Another thing, there should be support for sheeting under wing. That is easily formed using refuse from wing ribs.


That fits well enough.


Beginnings of hatch for elevator screws. I do not like idea of leaving nylon-screws (or anything else for that matter) visible.

Tuomas

[VincentB]

Great work have you thought about how to build the landing gear with ski, to be enough strong? it could be removable for landing on the grass?

[tuootal]

VincentB - thanks. For display use I will propably build 'scale' ski's. But for any kind of flying those original skis are totally out of question. I think here in Finland we know thing or two about skis and snow. With typical winter snow and plane of this size & weight those scaled skis would sink into snow immediately.

I doubt that they have ever worked unless original landing place was lake ice. Those ski's look typical cross-country skis which propably could keep max 150kg on top of snow. If used in skiing. But landing is totally different thing.

For flying I will do simple wooden skid on fuselage bottom. You cannot see it on pictures, but quite propably there was one.

And today's dish of balsa dust...


Time to do simple hatch. First bottom support with opening for magnet.


And then another magnet.


Some balsa on top of hatch and then some sanding. Done. This hatch is on underside of plane this is acceptable.

Tuomas

[tuootal]

And then back to build.



Okay.. now those uppermost spars are spruce.. there is temporary bridging to keep pilot opening from collapsing.

And then to wingtips. After all kinds of different implementation possibilities I decided simply to make form.

And then plenty thin woodstrips glued to form. This will take ages to dry, but there's no hurry.

Tuomas

[tuootal]

Then to the wing tips. As they are moving (= ailerons :) they are somewhat challenging. And there is also another challenge. Airfoil is constantly changing at tip so it took me quite bit head scratching. And I am not completely sure that this will work out. The geometry is quite complex specifically at the tip where HQ blends into rounded 5mm thick airfoil.



Some initial fiddling..


That's an hinge. Full wing thickness allows rather intriguing structures. The front of aileron will be sheeted..


Just checking that darned geometry. This will be really interesting. Normally when you are building scale model you can check how the original looks like. But not in this case, as the only surviving photographs are at beginning of this thread. Have to improvise something.

Tuomas

[tuootal]

Hello,

I have been away for a while to do another project http://www.rcgroups.com/forums/showthread.php?t=1802213 but now I'm back. I need to get this baby to air as winter is nearing end and only 'scale' time to fly this thing is during winter. Original was flown only during winter.

So my aim is to get this ready for maiden before seasons first aerotow event. That is Arctic Hysteria, 15-17.3.2013 at Padasjoki, central Finland. So approx 1 month to go. And there are some minor details to be done.



Rudder almost finalized.

Aileron servo setup. This is quite complex thing. First those thick plywood parts are to be glued to wing. The 3mm liteply spacer is to be allow easier removing of servo as it is not glued to plywood parts. Removing it allows servo to move slightly inwards.

And now servo is in it's place. There are still supports missing. Removing servo is simply a) unscrew servo wheel, b) unscrew servo via opening at the end of aileron bay. c) remove servo.

Aileron (actually wing tip) is removed via moving hinge pin into wing, as there is room for it.

All this might sound slightly complex, but I think I have thought it out and it *should* be working... With emphasis on word should...

Tuomas

[tuootal]

Okay, now I have done the first implementation test. It seems to be working, but there is some finetuning to be done.



First the actuator plate is cut into shape. Then the slider groove is milled into it. This is quite delicate stage as too large groove causes unnecessary play. Plate is from 1.0mm (or was it 1.5?) glassfibre plate.


Second stage is to cut keyhole for installation phase.


And then cut sunk openings for screws.


Fitted into aileron. Which is really wing tip :).


Finalized product. I have to tidy everything and sand aileron into shape. But it seems to work, which is most important thing.

And short video to prove that.

http://youtu.be/9mhpHPuH4Ak

Tuomas