1/32 Curtiss SC-1 Seahawk

[Martinnfb]

Slipstream created by propeller is usually dealt with by the angle or the shape of the vertical stabilizer or rather bf trim tab on the rudder. There must be a simple reason, like providing the access for removing the dinghy from its given compartment.  

 

[HubertB]

I assure you that the rear canopy windows were removed for aerodynamic reasons, because of some vibrations and turbulences, Martin. Not to access the raft, when the canopy would have been jettisoned anyway if the raft was needed.

Hubert

[Martinnfb]

I can't provide any assurance, only assumptions.  

However, for some reason, the SC-2 with bubble canopy had an additional/new  dinghy hatch on the side of the fuselage. So my question is, with the unframed bubble canopy there was suddenly no need for prop wash phenomena remedy?

Having said that , if you look at the color picture in my previous post , the raft bag is sitting right there, blocking the slipstream passage with only oner way to access it.

[DocRob]

Could it be, that the drag was too big, when flown with the open canopy? There would be a much better airflow with the rear windows removed.

Cheers Rob

[Martinnfb]

Philosophy starts by finding the things that are prosaic, utterly mysterious.

The only reason to fly with open canopy would be better visibility, that would lead to the new frame-less canopy development and an issued order, "don't do it, so we don't have to cut extra holes into it..."    

 

Mom, how we are going to service the raft? And what will happened to the raft once we jettison the canopy that this this is obviously sitting on?

Look Mom, fabric covering of the raft access hole, can I rip it for better aerodynamics ? 

Oh look Mom, the fabric is still on, sucks to serve on Iowa with such prop wash.

look Mom no drag to speak about  (final phase of landing-drag sensitive).    and that's one big propellor 

 

Look Mom no additional drag to speak about on the take off either and my canopy has no extra holes. (initial catapult assist take-off)

 

 

[BlrwestSiR]

The canvas cover definitely makes sense. The fasteners certainly line up with the holes on the ones without the covering. 

The blown canopy looks like a P-47 bubbletop. 

[HubertB]

Martin,

it was standard, and approved, and even recommended, by the Navy, practice to take off with the canopy open. Just, besides the « old » tradition of flying open cockpit biplanes - which endured for some time -, because pilots wanted to be able to escape quickly an aircraft that had missed its take-off - or experienced a power failure in this critical moment - and chosen to play watercraft rather than aircraft. And they did not trust that much the capacity of a latched canopy to be jettisoned easily in case of an inadvertent ditching. The practice endured until the early jets; the last being able to fly with an open canopy was the F9F-8T, the famous Twogar.

At take-off and landing speeds of these propeller aircrafts, an open canopy did not create that extra drag. Just like the windscreen of a convertible protects its occupants from the relative wind. And without significant turbulences for close to one meter after the windscreen, or more when you add some special aerodynamic devices behind them, like « anti-turbulence nets ». I can testify having run a Porsche Boxster with an open top at 230 kph without any special buffeting (but with some significant noise  ).

The bubble canopy was only possible after the Brits found a way of forming thick perspex, and that was during WWII (around 1943 IIRC). Before that, you had to have a framed structure with panels, like on the SC-1, whereas the SC-2 could benefit from the technological advance. But the SC-2 canopy had a slightly different profile and plan view than the SC-1, simply because it was possible when the SC-2 was developed. Plus it was certainly « cleaner » from an aerodynamic standpoint than one with protruding frames and rivets. As for the SC-1 canopy, the issue, it was found, was some significant turbulences and buffeting, created by aerodynamic interactions. It was also found that removing the rear panels solved the issue, and this was an easy field implementation. Really, I insist, nothing to do with maintenance of the life-raft, which had, on the SC-1 as any other aircraft, to be extracted from its location for this operation.

Hubert

 

[Martinnfb]

Hubert, we all understand why the canopies are open on approach and take off.  You came from guessing to a making solid statements such as " it was found" etc. Can you back it up by any kind of evidence or documentation?  Probably not and yet you insist.

 I provided pictures showing the few facts in contrary to your assumptions.

• There is a raft sitting on the frame. If you jettison canopy, you most likely loose the raft too.
• There is a fabric cover, or whatever is left of it, to provide cover of that particular compartment. 
• Bubble canopy of sc-2 has identical volume and shape as the framed one and does not contain the raft pack which was moved to the fuselage.

You started with a bunch of assumptions and now you stating what was found, by whom, when? With all due respect I am not buying it. 

Try to look at these these rhetorical questions. Why was there a cover? How do you access the raft? Why did they moved the raft into the fuselage with the addition of the bubble canopy? And provide me with some solid base to support your argument.  I will leave it with that.

Carl apologies for polluting your build thread.

[HubertB]

Martin,

You know me enough now to know when I make conjectures - which I then state as such - or when I relay information and knowledge gained from others’ expertise. And when I do not know about a subject, I just either say so, or just simply shut up.

I’ll post the relevant scan of the « Naval Fighters » book when I have more time.

Hubert

 

[Martinnfb]

I understand and don't want to turn this into a personal fuss . Any factual input would be greatly appreciated. And since this has become a huge bug in my head, I just purchased a scan of the USN Pilots handbook for the Curtis SC-1.  Its not a bible, but here is what I've learned so far.

• Canopy does not jettison 
• Single, parachute type personal raft is attached to the pilots harness. Stored by the seat bucket.
• Sea rescue provisions including Mae West life jacket are stored behind the armor head rest, that folds down forward for pilot to access it.
• There are miscellaneous "loose" provisions, intended for cold weather use, which some is stored at the same compartment 
• Directives on take offs and landings are "canopy open"
• Regulatory drag efficiency diagrams are related only to the cooling flaps position.

 

[HubertB]

Hubert

[jep1210]

I have no insight on the removed panels on the canopy but the build is looking mighty fine.

[Martinnfb]

Thank you Hubert.

[DocRob]

Call me Sherlock, gents . No idea about the real plane, but imagination 

Cheers Rob

[HubertB]

34 minutes ago, DocRob said:

Call me Sherlock, gents . No idea about the real plane, but imagination 

Cheers Rob

And also repeated in the text left of the captioned picture …

Call me Dr Watson, Rob 😂

Hubert

[Martinnfb]

Ohhhh, you are the cheeky bunch aren't you?  I stand corrected.  Next time state your sources.

[DocRob]

1 hour ago, Martinnfb said:

Ohhhh, you are the cheeky bunch aren't you?  I stand corrected.  Next time state your sources.

I had none, just an educated guess .

Cheers Rob

[HubertB]

3 hours ago, Martinnfb said:

Ohhhh, you are the cheeky bunch aren't you?  I stand corrected.  Next time state your sources.

Granted I should have done that earlier. Sorry.
 

But then, it would have been like a tennis match with just aces. So much more boooooooooring 🥱 than a lively exchange 😉

Hubert

[BlrwestSiR]

So, I wonder if the canvas was for weathering sealing the canopy when the planes weren't used? Or why it's there in the photos Martin posted. 

Back to the model bits, I tried the Dunkin' donuts route and dipped the canopy in AK Gauzy. First time I've done this.

Looks like they're clearer. Once it's fully dry, I'll mask and paint the framing. 

[HubertB]

According to photos on the Naval Fighters book, this seems like a one-off trial on a pre-series aircraft, Carl.

Hubert

[GusMac]

29 minutes ago, BlrwestSiR said:

So, I wonder if the canvas was for weathering sealing the canopy when the planes weren't used? Or why it's there in the photos Martin posted. 

Back to the model bits, I tried the Dunkin' donuts route and dipped the canopy in AK Gauzy. First time I've done this.

Looks like they're clearer. Once it's fully dry, I'll mask and paint the framing. 

What are your thoughts on the Gauzy Carl? I've never seen anyone using it before but the canopy on the Infinity Val look like they might benefit from something like this. 

[BlrwestSiR]

Gus, I've never done the canopy dip before using Future  or any other product so this is a first for me. I've had it for a bit so thought this might a good chance to try it.

I dipped the pieces straight into the jar,  it being just big enough. Then I left them under a cover on some paper towel to dry. The finish felt a bit soft along the edges still but that's where it pooled so it may not have fully dried yet. I'm going to let them sit a bit longer and then see.  

[Martinnfb]

1 hour ago, HubertB said:

According to photos on the Naval Fighters book, this seems like a one-off trial on a pre-series aircraft, Carl.

Hubert

If this is written in the book form Billy Jack Long, then he is wrong. 

Both pictures are showing well used operational airframes, with full marking. I believe those coverings are part of storage/cold weather package. Pending confirmation upon arrival of my SC-1 maintenance manual.

Source of the first picture, Naval Air Material Center, Report #N-4759, Rev.-1, May 1948, "securing and Storage of seaplanes aboard Battleships and Cruisers "

(This is not a Curtis corporate manual, based on the early production models, but official US Navy issue publication, using well worn, operational examples )

Location: US Naval Base Station Philadelphia, PA.  

Source of the second: unknown, dated 1949 decommissioned from USS Iowa, after years of service, making place for helicopters.

And just to add some pictures. Here is a pair, still operational aboard Iowa, dated 1947

 

 

[Martinnfb]

Full size pictures from the storage manual.

 

[HubertB]

You may be right, Martin, and me wrong. I have not reread the book in full, just skimmed through it yesterday looking for the references on the canopy, and stumbled on the pics you had posted. I may have misinterpreted the caption.

Lemme check again, just for the sake  of accuracy.

Hubert