Gloster Sea Gladiator (Halinski 1:33)

Thanks, JC. It is indeed a small model.

Quote from jcvandenbergh

But these two trumpet like horns on the second picture pointing forward between the cylinders...?

I was guessing at the guns as well, but I now see that it can't be so. The Lysander has the same trumpets (since it has the same engine). Here's a photo of a Gladiator which might give us some clues (and we can add a previously published photo as well, for a view from the other side, this time with the engine attached):

Note how the air intakes lead to something that looks like a cooler, since it has an outlet on the fuselage side as well. So I'm guessing at an oil cooler. I think you can find a marking on your model as well, which would correspond to this outlet.

If we take another look at another previously published photo, we'll see that this outlet is not a straight opening, but have something looking like a lid on it with just half a hole:

Interesting to hear if someone actually could tell us for sure if this is so.

Leif

PS. Exquisitine photography. I guess the new forum software helps as well.

Hey, Folks,

regarding the intakes: you´re quite good, Leif. I just checked my book with al these technical drawings. Not a plan of the Gladiator, but of the Bristol Blenheim which has nearly the same engine. It says "Oilcooler intakes".

Cheers

till

Man kann sich den Baubericht ja einfach nur ansehen - nicht jeder muss zu allem seinen Senf abgeben.

Wilfried, Du hast absolut recht. Über 19000 Klicks und keine 130 Beiträge sagt schon alles. Auch ich gehöre jedoch zu den "Nichtschreibern". Habe immer wieder in diesen tollen Baubericht gesehen und nur gestaunt. Die Anmerkungen der Profis waren sehr fundiert und von hoher Kompetenz (incl. passender Bilder). Ich glaube, das war der Grund für mich "Greenhorn" mich aus dem Austausch der Fachleute eher rauszuhalten.

Aber ich will mich gar nicht rausreden, JEDER kann natürlich seiner Bewunderung über einen so hochwertigen Bau Ausdruck verleihen und das möchte ich (Dank Deines " Wachrüttlers") auch tun.

@JC: Auch ich habe, wie so viele, Deinen Baubericht von Anfang an verfolgt und bin von jedem weiteren Bild des Fortschrittes schwer begeistert. Inzwischen dürften es nur mehr ein paar Tage sein und ein weiteres Meisterwerk wird die Galerie bereichern. Ich bin mir sicher, das Dein Bericht noch viele Kartonbauer dazu bringen wird, dieses Halinski Highlight ebenfalls anzuschneiden (vieleicht schon bald der Wilfried?) Ich kann die Bilder der fertigen Sea Gladiator jedenfalls kaum erwarten und wünsche weiterhin gutes Gelingen.

Eine gute Nacht wünscht:

J.R.

Etwas weniger ist manchmal mehr. Oder? Aber am Ende wird er schon ausgiebig gelobt, auch ohne Deine Aufforderung

Das Modell ist absolute Klasse!
Und zur Diskussion selbst; es klingt vielleicht etwas blöd, aber viele sind in Englisch nicht so mächtig, um auf Forum in diese Sprache zu schreiben. Diesen (mich inklusiv) bleibt dann nur, es
in stiller Bewunderung zu betrachten...

Quote from jcvandenbergh

"Ja...was soll Ich jetzt dazu sagen..."

This, Fellow, was kind of damned nice....

Quote from jcvandenbergh

Please don't ask me to get involved in this discussion, but believe me that I am very well aware of the feelings of sympathy that it reflects and the interest that you guys take in this build.

I would say, you don´t have to of course. I agree with Wilfrieds reminder, but it seems that your reports have always the potential to set up nearby discussions about cables/wires, letterboxslots, whatever, and the neccessity to stroke the authors/builders back with written feed backs. You seem to be a kind of guru, or so, hehe. Just a point of cristallization, as said before.
Be shure of feelings of sympathy. Not only for this build here.
And now, buddy, finish this ship, and start the next one. I´m waiting for it.

Cheers

Till

---

So why not show you two pictures of the propeller in place:

(Funny: So close to the finish line I managed to discover two small bugs in this superbly designed model: strips 47f and 47h at the rear of the propeller hub are too large).

** I will be back soon after a very short break to show you the final steps in the assembly of this model.[/quote]

Dear JC,

Today I must tell you that I have grave doubts about your propeller. My first impression was that it did not have any pitch (different angles of attack along the prop blade, very large at the root, almost none at the tip) at all. The direction of rotation is - as with so many British engines - counterclockwise seen from the pilot. You seem to have got that right, but even that was difficult to ascertain.

I looked up all the photos of Gladiator propellers I could find. Most of them were two-bladed, like this one:

Here, the pitch is clearly visible. But it is two-bladed, and doesn't count. So, with the first three-bladed prop, things started looking a little bit more like your version:

Even though it looks more like your propeller, you can see quite a lot more of a pitch than I can find in your model. Note also that the propeller seems to have a sort of common bottom plate for all three blades, Perhaps even going outside the spinner. Let's have a look at another three-blader:

Again, this looks a bit more like your model, but the change in pitch is still clearly visible. Finally an artist's impression:

Here the pitch is very much evident, but since it is an artist's impression, it doesn't count. Although it might be helpful in other respects.

I don't know what to do about this. I'll just leave it to your judgement, to decide whether there is anything to be done about the prop, or whether it is in fact alright as it is - the similar angle of your two shots may not have told the whole story.

I hope you take this the way it is meant. It would be such a pity if the prop should turn out to be the thing marring an otherwise perfect model. The propeller is such a visible part that it makes a heavy mark on your overall impression of a model.

Kind regards, Leif

Hello Leif, hello JC,

the first Gladiators of the first (production) series had propeller with two blades. Later, these planes got a more powerful engines that efforted 3-blades propellers.

Cheers

Alfred

Dear Friends,

I havn´t noticed that, but you´re right, Leif. The Pitch could be more visible - the direction of rotation on the other hand is not misunderstandable. If the blades are proper sticked together it might be a bit difficult, but from my experience it should be possible, to adjust them carefully - not with moisture this time. Would add some reality to the Gladiator, JC.
Anyway: wether you decide to try it or not - it´s a damned great little bird.

Cheers - let´s have some champaign

Dear JC

I sincerely hope I haven't made you feel bad about your great build of the Gladiator. I was honestly trying to address a perceived problem on the same high level as you have conducted your build, as well as your build thread. I know you as a most conscientious builder of many kinds of models, so I thought that perhaps you were not necessarily familiar with propellers.

It took me a long time to understand how a propeller really works - thinking of it as an "airscrew" chewing itself into the air like a corkscrew into a wine bottle is really not that helpful. Far better then to understand each propeller blade as a wing, which needs to meet the stream of air at an optimal angle at each point along the blade.

The problem is that the stream of air meeting this rotating wing - the prop blade - has a different direction at each point along the blade, from the center outwards. This is because it is a resultant of two airstreams - the one from straight ahead, caused by the aircraft's movement through the air, and the other from 90° to this, around the clock, caused by the propeller's rotation.

Close to the center of the prop, the airstream from ahead is about as strong as the airstream caused by rotation. Therefore the blade must be angled roughly 45°.

At the periphery, the airstream from rotation is much stronger than the stream caused by the airspeed. Therefore the blade has a very shallow angle (pitch).

It would be quite possible, and not too difficult, to sit down and calculate the required angles at different distances from the hub for an ideal Gladiator prop - with proper knowledge of engine r.p.m., prop diameter, and the gearing of the engine (lower prop r.p.m. than engine r.p.m.). Note that if you don't have a variable pitch propeller (and the Gladiator didn't have that) such a calculation would have to be a compromise, optimal for one airspeed only. Therefore, a fixed pitch prop is seldom or never optimized for take-off speed, but for the airspeed where you wish either maximum effect or maximum fuel economy.

As model builders we don't have to go to that extreme. But some effort to reflect all these concerns is always nice, I thought, and it will be noticed also by people not familiar with every aspect of propeller making. After spending some time looking at various propellers you get a kind of feeling for what looks "right" and what doesn't. I just thought your model deserved having something looking a bit more "right".

Here are a few more drawings and photos. First a couple of drawings from the airwar.ru site:

In the sideview, you will get an idea of the degree of pitch to aim for. The frontview gives a pretty good idea of the shape of the blades. The photo below is of a three-bladed prop, but not one you would like to model. The source states "Faith (serial number N5520), a Gloster Sea Gladiator Mk I, on the ground at an airfield in Malta, in about September 1940. The aircraft has been refitted with a Bristol Mercury engine and three-bladed Hamilton propeller salvaged from a Bristol Blenheim."

Therefore, pay no attention to that propeller as such, since it is a variable-pitch propeller, and I don't think the Gladiator had any such options. But it will give you an idea about the degree of pitch for any Gladiator propeller. As displayed today, in a Malta museum, this aircraft has a two-bladed propeller. Here's a more interesting photo:

The caption says: "Late series Belgian Gladiators with Fairey 3-blade propellers". The same kind of prop seems to be attached to these Gladiators:

It is a nice photo, and you get an idea of the pitch of the props, but it is still from a distance. Better then a close-up of a photo we've seen before:

I believe this might be a close-up of the Fairey Reed 3-blade propeller mentioned abover, but I am not sure. It is a most strange propeller, almost flat it seems, and therefore seemingly easy to model. But it was still twisted (of course), and hopefully this photo might be of some help in getting the pitch right. Notice how heavily the blade is twisted close to the centre, much less so towards the periphery.

Warm regards, Leif

Dear JC,

Could I impose one more photo upon you?:

This Wikipedia photo is of a Bolingbroke MkIV aircraft, the Canadian-built Bristol Blenheim. The point here is that it was powered by a similar Mercury engine as your Gloster Gladiator. I chose this photo since it demonstrates so well what I wanted to get across, namely the widely different angle of the propeller blade at the centre and the tip. As we have already said, it is not the same propeller as the Gladiator (this one has adjustable pitch), but the point here is to illustrate the twist of the propeller blade.

Any propeller which wouldn't be totally inefficient would have to feature a similar degree of twist of the blade, that is my point.

Enough already...

Leif

Once I've started down this road, I feel a responsibility to travel it all the way to its end. This post should give you some hope - Fairey-Reed propellers are rather special, and it is possible that your model is closer to what they looked like than I thought from the start.

Here are photos of antique two-bladed Fairey-Reed propellers for sale on the internet today:

The last attachment (two photos above each other should give you an idea of the twist. But these props are still remarkably thin!

Here are a number photos of another two-bladed Fairey-Reed metal prop for sale:

Even though they are not of a three-bladed Fairey-Reed Gladiator prop, these photos of that particular brand of propeller may be helpful for you to get an idea of what to aim for.

Best regards again, Leif

Dear JC,

nice to hear from you.
Thanks for your explanations about the prop. I assumed something like this. I faced more or less similar problems with the props of the Comet. The pictures show exactlly how much the blades are twisted, BUT .....to copy this for the model was nearly impossible.
Anyway, never mind. as said before: this is a fantastic Gladiator and only comletly mad people like me realize this difference between the model an the real thing.

Cheers

Till

I am glad that my original suspicion from the first post discussing the propeller turned out to be correct:

Quote from Leif Ohlsson

...the similar angle of your two shots may not have told the whole story.

And, likewise, the observation about the particular kind of propeller of the Gladiator in the last post discussing the propeller:

Quote from Leif Ohlsson

Fairey-Reed propellers are rather special, and it is possible that your model is closer to what they looked like than I thought from the start.

Clearly, both these statements are true both of the Halinski design, and your build of it.

That being said - and I'm glad to fully concede both of these points - would you mind very much if we philosophized a bit further about propeller making in paper modeling, using your propeller as an example?

The main thing about propellers is that the "twist", if we may use that term, is largest close to the center, and very small at the periphery. Paper model designs usually solve the problem of modeling this feature by glueing the propeller blades at a compromise angle at the spinner, let's say 30-45°. In the best of cases, the design then provides directions for the builder to reduce this initial twist towards the periphery. Or the modeler might do this on his or her own initiative. This is a fairly straight-forward problem (at least in theory) for thick wooden props, and actually quite doable for adjustable props, like in the DH88 Comet and most WWII aircraft, where the propeller root is almost circular. There, the problem is much easier to solve, both for designers and modellers (although not always easy to carry out in practice, as we all have experience of).

Yours was a different kind of problem. The Fairey-Reed propeller is very thin and very flat at its center. Therefore, there has to be a very marked twist very close to the center, which in fact makes the prop, as seen from the side, seem thicker than it really is (see the photos and drawings of Fairey-Reed propellers). From this early heavy twist, the blades are then twisted back again towards the flat initial condition of the thin center as we get farther out. (Incidentally, this is not always clearly shown by drawings, but always in photos, which goes to show that the persons making the drawings have not grasped the character of this kind of propeller either...)

I now realize your problem, which stems from how the designer tried to solve this challenge. You described very well how the designer had tried to induce the early heavy twist by the small wedge-like parts. This part, you did not have any control over. Whether this is good or bad, I can't say, but at least it speaks very well of the Halinski model designer that he or she obviously has realized the special challenge brought by the Gladiator propeller.

The problem, as I now understand it, boils down to that from the point you mentioned - where you could actually control the amount of twist induced - from that point on one should actually reduce the twist already induced by the wedges.

The challenge this kind of propeller and the particular paper model design of it introduces, thus is to introduce as much "twist" as possible in the short section close to the center (controlled by the wedge-shaped parts), and then reduce the amount of twist introduced here as we continue towards the tip.

Of course, if one realizes that the aim of the design is to introduce this very heavy twist in a short length of prop blade closest to the center, and then decrease this angle again as we go towards the tip, the chances of a successful build increases.

Not easy to grasp, that: The Fairey-Reed propeller has to be twisted twice, from a low angle (necessitated by thin center) to a high angle in as short distance as possible ( as necessitated by propeller theory), then gradually back again to a low angle at the tip - while an ordinary thick or adjustable prop only has one twist in it, back from an initial high angle at the center to a low angle at the tip.

With this I am quite happy to leave the propeller discussion for now. And I do look forward to the finish of your exquisite model. Let me just say that I learned a lot I didn't know before (never heard about a Fairey-Reed prop, never seen a photo of one, never thought about the challenges posed by it until seeing your build - and not really understanding the magnitude of the challenge until this very moment, after seeing your final photos and reading your explanation of the design).

Leif

PS. I do hope you had a good time during your short leave of absence. A little bit of vacation?

Hello JC,

you have done it again, what a great plane this turned to be !

It was fun to follow your build and enlightening to follow ths discussions.

Zaphod

Hello JC,

The model looks very good, you've done a great job

best regards
Günni

Hello JC,

you made a very fine job at this plane - the result confirms this.
Thank you for your informing build report.

Kind regards

Alfred

That is an realy cool model and I thik i want to build it too.

Hi JC,

it was very very interesting to follow your build of this excellent little Plane. But now its done and ,now Wonder, it looks fantastic.

Thank you, for sharing this build with us!

Cheers

J.R.

She's a real beauty! You've done a wonderful job on this well designed kit.

May I ask for some more (and bigger pictures in a gallery?

Old Rutz

Congratulations! I really like the sideview, in particular:

Leif

Thanks a lot - I love this plane with its archaic shape (although I'm addicted to jet planes