Technote: P-38 Lightning Dive Flaps
This is what I am working on now: the P-38 Lightning Dive Flaps. At the moment this is a multi-body part file which I will then extract as separate parts and then assemble. The plan is to also include all the mechanical components to analyze operational criteria.
I shall add to this post as this part of the project progresses and perhaps add some notes on Simulation within Inventor. I should note that the external panels are actually transparent to show the internal lightening holes depicted in these images.
Update Dec 7th 2022:
The mechanical components are now modeled and temporarily located in the Dive Flap assembly. It is actually quite a substantial mechanism that is currently missing the main hydraulic operating cylinder. That component is a contracted supply unit for which I do not have any details so the simulation will use a proxy component for purposes of evaluation.
Before I get around to doing that I must first locate it on the underside of the wing…that will need to be partially modeled with local ribs and struts in order to define the fixing bolt locations.
Update Dec 8th 2022:
Another day, another update. I now have the rib at Station 146 and 158 modeled primarily to assist with positioning. The Lockheed layout drawing for this assembly is not included in the archive so I had a lot of research to do to get this thing in the correct position. What I noticed is an access hatch on the underside of the wing which this assembly effectively replaces so that was useful in this task, though I had a lot of rivet holes to position to get it right!
You will notice that the assembly now has the operating cylinder…I was lucky to find a drawing for this that provides much-needed data for maximum and minimum travel. Actually, I call it an operating cylinder but technically it is a linear actuator gearbox.
When I inserted this item into the assembly it provided a positional check on the main assembly.. which incidentally was perfect.
A few bits to tidy up and then move on to a simulation…I shall upload a short video to Youtube when that is done.
Update 9th Dec 2022:
I have cobbled together a quick video showing the operational aspects of the P-38 Dive Flaps. I am working on a more detailed video which won’t be ready for a few days…so check out this short version for now and let me know what you think.
The technical bit: Each of the 3 flap panels comprises 3 layers of sheet metal with a total thickness of 0.18 inches or 4.572mm. The mechanical assembly is fitted between Ribs at Station 146 and Station 158 and driven by a Linear Actuator. The Dive Flaps were designed to be retrofitted to P-38 Lightning prior to P-38J which explains the location of the main support frame which aligns with the hole centers for a wing access panel and the forward panel fitted forward of the main beam. For reference, I have included a selection of design operational data and some close-ups of the mechanism. that you may find interesting below.
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