A bit of good news. I apparently have the only remaining D.H. 108 Swallow blackline print in existance...
After an exhausting search it turned up in the last place we viewed it... Seriously, it had been placed in
a most secure location...almost too secure.

Though it is one of only two or three of the remaining Jack Lynn Bale black line prints it is well preserved.
Later this week it will join our growing number of digitized original vellum and prints for preservation.

Every JLB plan sold is a printed black line plot of a digitized original, or reengineered enlargement of
same. These are not copies of copies...no swollen Xerographic lines. Each sheet is an original inked
black line "plot" at the width inked by Barbara Bale.

My last try. 

Chance Vought f7u-3 cutlass

What about it makes so many folks think its a jet? Actually jets were its nemesis.

The XF5U was originally designed with four blade props but vibration issues required replacement with F4U-1 three blade props. 

1. The XF5U-1 was taxi tested using 4 blades propellers from an F4U-4. The vibration levels from the gearboxes and propellers were so svevere that the only proper place to possibly test fly the "Flying Pancake" was Muroc (now Edwards) Air Force Base. That would require transfering the aircraft by a barge to the west coast.

2. The F4U-4 blades were deemed to be inadequate and Chance Vought built special blades. That delayed the program another year until 1947 at which time the Navy decided that the project was of no value anymore and cancelled it altogether.

3. The XF5U-1 was never intended to have 3 blade propellers, those were used on V-173 which was a feasibility demonstrator

No pun intended. 

Josh

 

So Clue #3   was the pair of 4 blade props used on the F4u.

The picture after the clue of the 2 drop tanks through me off. LOL