Tiffie Question

[Brad-M]

Hi Guys,

 

So besides being able to see the larger horizontal tail planes, is there a way to tell if a Typhoon has them? Do they go together with the 4 bladed prop?

 

TIA

 

Brad

[gingerbob]

As I recall, if the 4-blade is fitted the tailplanes will (normally) be Tempest type, but you can also find Tempest tailplanes on a Typhoon with 3-blade fitted.  I know that there are more detailed answers around here...

[Work In Progress]

There is certainly a high correlation between 4 blade props and Tempest tailplanes. I can't swear that it is 100% as retrofits happen. 

[Roger Newsome]

When I built mine I learnt the only way to know is to find a photo of the particular aircraft you are building and in the time frame you're depicting it. (Before or after modification, if it received one).

Roger.

[Graham Boak]

Except for test airframes the four blade prop required the larger tailplanes because otherwise the aircraft was unacceptably less stable.  The large tailplanes went into production before four blade props were available so you will find them on airfames with three blade props.  Many Typhoons were refurbished but if they retained the small tailplane then they retained the three blader.

 

Memory suggests that such aircraft were preferentially sent to to rocket squadrons but that this was not an absolute rule.

Edited March 26, 2019 by Graham Boak

[gingerbob]

OK, here's a statement from Chris about tailplanes.  Note that this thread is 10 years old, so it is possible things have evolved, but it is a start.

 

Graham, what I "remembered" (or thought I did) was that the 4-blade- or was it just the big tailplanes?- was needed for 1000 lb bombs.  I'm not sure what you had in mind with your last comment (which "such aircraft" are you referring to?)j

 

bob

[Graham Boak]

I used to think that the big tailplanes were required for the 1000lb bomb, and hence preferred for bomber squadrons.  However IIRC Chris could find no such reference in the service release documents and even  found at least one example where a unit carried 1000lb bombs on a small tailplane aircraft.  (This is from memory, but I don't believe I've altered the basics.)  We can assume this wasn't just a mistake...but should remember that reduced stability does not necessarily mean totally unflyable, just perhaps too much of a handful for the average pilot to be safe with.  However, getting back to basics, as the bombs were carried close to the c.g. to ensure little change in trim once they were dropped, perhaps it makes sense for there to be little link to the size of the tailplanes. 

 

I still feel sure (memory again?) that there was a preference on the distribution of the two options, as said above, but can't quote a source.  OK, perhaps I should look for one, but if you are modelling a known serial and a known unit, you already have what you need anyway.

 

 The 4-blade transmitted slightly more power and produced less vibration, this being a Good Thing in two ways.  The need for this might well be related to the general increase in power of the Sabre with time, although I believe that the only difference in the Sabres installed with 3 and 4 blade aircraft was the propshaft.  This did mean that you couldn't just switch props without changing the engine.  However there being more metal flying about at the front affects something called disc solidity (I think that's the right term) which is destabilising.  Which apparently was no problem with the vertical fin (directional stability - yaw) but did require more horizontal tail area (longitudinal stability - pitch).

[Brad-M]

Thanks for the replies everyone! It's much appreciated. I will look for photos of my planned subject "Pulverizer II", MP149 of RCAF 440 Sq. and go from there.

 

Cheers,

Brad

[Roger Newsome]

4 minutes ago, Brad-M said:

Thanks for the replies everyone! It's much appreciated. I will look for photos of my planned subject "Pulverizer II", MP149 of RCAF 440 Sq. and go from there.

 

Cheers,

Brad

There are decals for "Pulverizer II" on Xtradecal sheet X72179. On the info sheet it says, 440 Sqn., 2 TAF, B78/Eindoven, circa Dec 1944.

Prop-4. Tail- Tempest.

Ref. 2 TAF Vol.3, P.414, RAF Squadrons-Jeffors P.93.

Hope that helps. 

Roger.

[gingerbob]

Here's a shot (click to embiggen).  Judging from the position of the Sky band, I'd surmise Tempest tailplane.

[Denford]

Though I haven't re-read it, I do recall the original thread on this.

It was the intention that the enlarged tailplane and 4 blade prop' would be used, exclusively, together.

However, initially, there were problems with the seals on the new propellers, and some a/c were retrofitted with 3 bladers until the problem was resolved.  By implication, when the problem was solved, the propellers were changed back to 4 blade units.

So a 4 blade prop always meant an enlarged tailplane but not necessarily vice versa.

The advice, as always, was to check carefully.

[Graham Boak]

Not retrofitted but built on the line.  The change in the propeller meant a new engine variant because the spline on the propeller shaft changed.  They would not be fitted with the new prop without an engine change.  As I understand it.

[gingerbob]

That spline change is new to me, and I don't see why it would have to be different.  Of course, that doesn't mean it ain't so.  Didn't "one spline fits all" come in with the Merlin III back in 1939 or so?  I thought it was just a matter of, "Oopsie, can't seem to get these 4-bladers to stop leaking oil, better keep sticking 3-bladers on until we get it sorted."

 

Edit: Here's an article about the Sabre VII that's pretty detailed, though I didn't see mention of prop shafts.

...and one on the Sabre II.

Edited March 27, 2019 by gingerbob

[Work In Progress]

15 hours ago, Graham Boak said:

 without an engine change. 

Given the serviceability of the early Sabre, plenty of opportunities to change props, then...

[gingerbob]

In pursuit of "the spline question", I happened upon another comment from Chris - in this thread.  I'll post a couple of excepts, to see how well they go together: (drawn from different threads, both linked to in my comments on this thread)

On 1/17/2009 at 10:58 AM, Chris Thomas said:

Since I last wrote about this topic in MAM another photo has come to light which shows MN306 had the small tailplane. All from MN309 onwards had the large tailplane.

On 2/23/2009 at 6:26 AM, Chris Thomas said:

Tailplanes - if serial earlier than MN307 they should be small - if MN307 or later they should be large (Tempest size).

 

Since it relates, one more quote from one of the threads:

On 11/9/2008 at 5:56 AM, Wez said:

Having re-read the MAM article, Chris Thomas states that 4-blade props were the norm by MN601 but that aircraft could could come off the line after that with 3-blade props to fill gaps in 4-blade prop availability.

 

 

And just in case anyone wants to read about the distinctions between SBAC and SAE spline standards and so on... Hey, there IS mention of the Sabre, at least...

Edited March 28, 2019 by gingerbob