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Search: Posts Made By: Marc Bourget
Forum: RV Building Tips/Techniques 05-03-2021, 12:09 PM
Replies: 4
Views: 402
Posted By Marc Bourget
Have a scrap strip of aluminum that you can use...

Have a scrap strip of aluminum that you can use to make a transfer strip?

Make sure you maintain up from down and right to left (don't ask why I mention this! :D)

Use it to compare skin to new...
Forum: RV General Discussion/News 02-13-2021, 11:39 AM
Replies: 24
Views: 1,986
Posted By Marc Bourget
The potential problem with these "one on one"...

The potential problem with these "one on one" relationships is the ability not only to track hours, but the equivalent value of the work performed by your partner.

With my background (and...
Forum: Alternative Engines 02-06-2021, 05:47 PM
Replies: 95
Views: 9,861
Posted By Marc Bourget
Any report on the mechanism of failure in the...

Any report on the mechanism of failure in the Raptor engine?
Forum: RV Building Tips/Techniques 01-27-2021, 07:07 PM
Replies: 10
Views: 1,271
Posted By Marc Bourget
A study sponsored by the Navy showed that...

A study sponsored by the Navy showed that matching a reamed hole to the bolt diameter (I have a set of stepped reamers .0005" that allows me to have a 0.00 to -.001 (interference) fit for AN bolts). ...
Forum: Safety 01-19-2021, 10:57 PM
Replies: 58
Views: 14,703
Posted By Marc Bourget
I was on approach to the Nut Tree on a Summer day...

I was on approach to the Nut Tree on a Summer day and was experiencing a little turbulence, at about 100', a foreign student passenger behind me panicked and reached forward and began choking me...
Forum: RV Building Tips/Techniques 01-16-2021, 10:20 AM
Replies: 9
Views: 749
Posted By Marc Bourget
I'm impressed with the amount of effort, and...

I'm impressed with the amount of effort, and sharing, of a technique managing opposing physical properties and effects.

I'm being truthful and sharing, not critical, as I'm speaking from the...
Forum: Traditional Aircraft Engines 01-08-2021, 12:10 AM
Replies: 3
Views: 1,096
Posted By Marc Bourget
The oil mist is substantial inside the case. ...

The oil mist is substantial inside the case.

Cam problems occur as stated above.

Showing my ignorance about aircraft oil additives . .

If you really want to go the extra mile, I just heard...
Forum: RV-14 01-03-2021, 05:11 PM
Replies: 24
Views: 3,326
Posted By Marc Bourget
Consider displacing the center lift backwards...

Consider displacing the center lift backwards with a yoke with a saddle down to the propeller so that the nose is slightly higher regardless of fuel quantity.

The slight leveling pressure, nose...
Forum: RV-6/6A 01-03-2021, 06:20 AM
Replies: 7
Views: 1,238
Posted By Marc Bourget
Appears that the aluminum angles haven't been...

Appears that the aluminum angles haven't been riveted yet.

Have you considered simply shrinking the flutes flat, by hand, the same way they form the SS firewall flanges without fluting?

If you are...
Forum: Tools 12-31-2020, 06:58 PM
Replies: 20
Views: 2,029
Posted By Marc Bourget
Caveat: Local building codes may require metal...

Caveat:

Local building codes may require metal pipe up to a certain height from the floor.

Early on, I "lucked" into a 110V AC refrigerated unit and I'll never have a fixed compressor without one. ...
Forum: RV-10 12-23-2020, 11:00 PM
Replies: 15
Views: 2,486
Posted By Marc Bourget
What do you expect to accomplish with the...

What do you expect to accomplish with the mastic?

If you're placing the mastic as a paint prep, there is no good reason for NOT stop drilling the end of the crack.

I know others have observed no...
Forum: RV-10 12-21-2020, 09:11 PM
Replies: 30
Views: 4,951
Posted By Marc Bourget
Jeff said: "Alternatively, if you are getting a...

Jeff said: "Alternatively, if you are getting a good result (i.e. a straight TE), then any realized mechanical disadvantage may be worth the cost."

Ah, yes, the ole elevating form over function...
Forum: Traditional Aircraft Engines 12-15-2020, 04:54 PM
Replies: 228
Views: 48,970
Posted By Marc Bourget
Rocket Bob said: "The FAA is saying the white...

Rocket Bob said:

"The FAA is saying the white layer is the root cause, so if its gone, problem solved."

I'm assuming the text after "cause" is Rocket Bob's and not the FAA's

A very prominent...
Forum: Alternative Engines 11-24-2020, 01:45 AM
Replies: 63
Views: 9,503
Posted By Marc Bourget
One thought about diesel aircraft engines. Spoke...

One thought about diesel aircraft engines.

Spoke with the Cessna engineer developing the 8 cylinder engine for the 182.

Curious about the choice of 8 cylinders.

He explained that the firing...
Forum: RV General Discussion/News 11-23-2020, 11:15 AM
Replies: 18
Views: 2,405
Posted By Marc Bourget
If you were flying into a head wind and your...

If you were flying into a head wind and your "effective" trip distance was 30% higher, are you limited to the published city-to-city distance figures?

:D
Forum: RV General Discussion/News 11-23-2020, 09:21 AM
Replies: 18
Views: 2,405
Posted By Marc Bourget
Interesting that the link to the GSA page worked...

Interesting that the link to the GSA page worked this morning but repeated attempts now result in "no joy"
Forum: RV Ongoing Maintenance Issues 11-21-2020, 06:25 PM
Replies: 18
Views: 2,904
Posted By Marc Bourget
I didn't see the filter, but can you mold in a...

I didn't see the filter, but can you mold in a grove that the ring on the filter will fit, trapping it so it dosen't vibrate?
Forum: RV Building Tips/Techniques 11-21-2020, 08:00 AM
Replies: 15
Views: 1,550
Posted By Marc Bourget
Didn't see a reference to the "Basics." Kinda...

Didn't see a reference to the "Basics."

Kinda like a "checklist", in this case a "pre-drill checklist"

What drill and rake angle?

(Don't ask me why I started using checklists - it'll probably...
Forum: RV Ongoing Maintenance Issues 11-20-2020, 08:43 AM
Replies: 12
Views: 2,421
Posted By Marc Bourget
Any chance you could acquire a forward...

Any chance you could acquire a forward bulkhead?

Or have someone make one for you?
Forum: Traditional Aircraft Engines 11-18-2020, 06:27 PM
Replies: 16
Views: 3,750
Posted By Marc Bourget
For the sake of more accurate communication, the...

For the sake of more accurate communication, the presence of the oil cooler near the hot cylinder doesn't "take" it provides an alternative path that reduces the "Delta P" in the vicinity of that...
Forum: Traditional Aircraft Engines 11-15-2020, 10:13 AM
Replies: 17
Views: 2,526
Posted By Marc Bourget
Rob, to keep everyone focused on the most...

Rob, to keep everyone focused on the most efficient path, Consider describing the activity as "forming" rather than bending.

I'm sure, in concept, you meant "forming" (3 dimensional bending).

It...
Forum: Electrical Systems 11-13-2020, 08:35 AM
Replies: 43
Views: 7,126
Posted By Marc Bourget
On the 2 to 1 pulley ratio. Showing I'm an old...

On the 2 to 1 pulley ratio.

Showing I'm an old fart, I recall the advent of Alts in automobiles. Powered accessories were increasing. The major benefit touted was charge output at idle rpm...
Forum: Electrical Systems 11-12-2020, 01:53 PM
Replies: 43
Views: 7,126
Posted By Marc Bourget
I apologize if this was raised earlier, here, or...

I apologize if this was raised earlier, here, or in another thread, but I would like to see a correlation between Alt rpm at peak rpm and cruise and MTBF (mean time between failure).

Before I "woke...
Forum: RV Building Tips/Techniques 11-09-2020, 09:43 AM
Replies: 15
Views: 2,468
Posted By Marc Bourget
Buying new rivets worked well in the early 70's...

Buying new rivets worked well in the early 70's in SoCal with all the Aerospace activity. Thursday morning at Fullerton Air Parts (Aircraft Spruce at that time was "down the street, dealt only with...
Forum: RV General Discussion/News 11-05-2020, 02:13 PM
Replies: 28
Views: 7,439
Posted By Marc Bourget
Ever consider visiting your congressman's office...

Ever consider visiting your congressman's office and showing him this original post and the stack of information provided in response to the various requests?

Be sure to mark the duplicate...
Forum: RV-10 11-02-2020, 01:44 PM
Replies: 5
Views: 1,332
Posted By Marc Bourget
While intelligent conversation, it can be...

While intelligent conversation, it can be postured as intelligent conjecture until verified.

I'm assuming Dan H's points was limited to lower speed operations, like climb out.

I understand the...
Forum: RV General Discussion/News 10-22-2020, 08:33 AM
Replies: 8
Views: 2,352
Posted By Marc Bourget
IMHI, a "finder's fee" should be supported by...

IMHI, a "finder's fee" should be supported by some consideration or effort expended by the "finder" to the benefit of the purchaser.

A simple referral based on casual knowledge would not appear to...
Forum: RV Building Tips/Techniques 10-18-2020, 02:58 PM
Replies: 5
Views: 1,471
Posted By Marc Bourget
Referencing Andrewtac's post. The "dimple" in...

Referencing Andrewtac's post.

The "dimple" in the skin created when the rivet was set can sometimes be raised back to level by backing the shop head with a bucking bar and LIGHTLY striking the skin...
Forum: Traditional Aircraft Engines 10-13-2020, 07:52 PM
Replies: 8
Views: 1,446
Posted By Marc Bourget
Don Pridham's Master's Thesis on Converting the...

Don Pridham's Master's Thesis on Converting the GPU answers these questions. I never heard anything about a longer camshaft. I visited Don frequently during his authorship and went with him to John...
Forum: RV-3 09-28-2020, 08:52 AM
Replies: 4
Views: 1,304
Posted By Marc Bourget
Quick thought Tuft the exits and look for an...

Quick thought

Tuft the exits and look for an aerodynamic "afterbody"

More or less the completion of an imaginary streamline body, a rain drop. In this case - approximately a 1/2 cone, sliced...
Forum: RV-12/RV-12iS 09-26-2020, 12:10 PM
Replies: 19
Views: 4,704
Posted By Marc Bourget
Talking Chips are unavoidable and ubiquitous. Touch up...

Chips are unavoidable and ubiquitous.

Touch up paint are what chips are made for!

It gives touch up paint a "raison d'etre"
Forum: RV-14 09-21-2020, 08:39 PM
Replies: 11
Views: 4,654
Posted By Marc Bourget
I'd like to share the technique taught to me by...

I'd like to share the technique taught to me by Aircraft Sheet Metal Pros working in Lockheed's and North American's prototype shops in WW-2 through the 70's. You want to put a slight bend to the...
Forum: Safety 09-16-2020, 05:26 AM
Replies: 26
Views: 7,362
Posted By Marc Bourget
I performed an inspection at Compton some years...

I performed an inspection at Compton some years back and in the next hangar parked in the corner nearest the road was a Beech Staggerwing, a DUI driver ran through the boundary chainlink fence,...
Forum: Safety 09-07-2020, 09:19 AM
Replies: 53
Views: 11,371
Posted By Marc Bourget
By distinguishing the folded vs. riveted trailing...

By distinguishing the folded vs. riveted trailing edge, are you making indirect reference to the Kutta Condition?
Forum: RV-10 09-06-2020, 11:33 AM
Replies: 23
Views: 6,572
Posted By Marc Bourget
It might be worth pointing out that the Lyc...

It might be worth pointing out that the Lyc cooling spec, depending on the engine typically installed in a RV, requires a Delta P of 5.5 or 6.5 " H2O.

That should be a baseline target as . . if...
Forum: RV General Discussion/News 09-05-2020, 02:42 PM
Replies: 14
Views: 2,241
Posted By Marc Bourget
After my stint with a stent, I found the...

After my stint with a stent, I found the following article to be helpful. My former AME (retired) is a friend of 30+ years. Shared this article with him and he clarified the "less than obvious"...
Forum: RV General Discussion/News 08-15-2020, 02:01 PM
Replies: 21
Views: 6,194
Posted By Marc Bourget
Gotta give him credit as the wing loading on a...

Gotta give him credit as the wing loading on a F-18 is WAY higher than a RV
Forum: RV Building Tips/Techniques 08-14-2020, 07:49 PM
Replies: 14
Views: 2,727
Posted By Marc Bourget
In my experience, ( two aircraft, minor work on a...

In my experience, ( two aircraft, minor work on a Bearcat and a wet wing project on a Sea Fury), I've never seen a pneumatic squeezer over-do a dimple.

The usual result is under forming, the dimple...
Forum: RV Building Tips/Techniques 08-14-2020, 10:44 AM
Replies: 14
Views: 2,727
Posted By Marc Bourget
Dittos on Norm's comment, but a good "rule of...

Dittos on Norm's comment, but a good "rule of thumb" for judging dimple quality is to put a rivet in the dimple and see how it fits.

Way I was taught, the dimple "passed" when testing the fit of the...
Forum: RV Building Tips/Techniques 08-11-2020, 10:33 AM
Replies: 2
Views: 687
Posted By Marc Bourget
I'm sure it's been mentioned here before! I...

I'm sure it's been mentioned here before!

I was taught to over bend, slightly, as the angle will relax a few degrees from (AN) riveting.

Curl the edge of the flange slightly to avoid "printing"...
Forum: RV Building Tips/Techniques 08-06-2020, 06:55 AM
Replies: 20
Views: 3,047
Posted By Marc Bourget
All of the above describe stress...

All of the above describe stress concentrations.

Low tech description follows:

In the design process, as you calculate mass concentrations as you progress through the design, you can evaluate the ...
Forum: RV Building Tips/Techniques 08-05-2020, 11:32 AM
Replies: 20
Views: 3,047
Posted By Marc Bourget
I've seen sheet metal fail (start cracks) because...

I've seen sheet metal fail (start cracks) because of poor deburring.

Taught by WW2 Factory workers in the 70's This was emphasized.

That said, I agree that novices tend to remove too much...
Forum: RV Building Tips/Techniques 07-15-2020, 10:26 AM
Replies: 2
Views: 1,160
Posted By Marc Bourget
Talking The following books also provide relevant...

The following books also provide relevant information, and, sometimes the same, just stated a bit differently.

I'm surprised at the times I read a reference book and overlook something, only to...
Forum: RV General Discussion/News 07-11-2020, 08:42 AM
Replies: 12
Views: 3,638
Posted By Marc Bourget
Carl, The presentation, IMHO, is beyond...

Carl,

The presentation, IMHO, is beyond excellent.

I benefited from 15+ years of mentoring by John Thorp. After his passing I contacted Martin Holman (noted flutter expert) to reinforce John's...
Forum: Alternative Engines 07-07-2020, 11:46 AM
Replies: 8
Views: 3,023
Posted By Marc Bourget
OSH, 2009, I had the privilege of having an...

OSH, 2009, I had the privilege of having an extended conversation with a Cessna engineer at the C-182 V-8 diesel powered model.

The major point I recall, relevant to the referenced 4 cyl. Lycoming...
Forum: RV-14 07-06-2020, 02:15 AM
Replies: 39
Views: 9,458
Posted By Marc Bourget
Steve said: "The real issue is the shallow but...

Steve said: "The real issue is the shallow but large crater around each rivet. "

Do you refer to the shallow dip or depression that occurs, for example, when "gun riveting" skin to a rib or formed...
Forum: Trip Write-ups 07-02-2020, 07:26 PM
Replies: 28
Views: 11,449
Posted By Marc Bourget
I liked it very much. Questioning why you chose...

I liked it very much.

Questioning why you chose "scars" of war rather than relics.

I'm curious, the pictures show aging, not battle damage.

Do you feel the old airfields should have been returned...
Forum: RV-3 07-02-2020, 06:34 AM
Replies: 11
Views: 2,540
Posted By Marc Bourget
If making your own, be particularly careful with...

If making your own, be particularly careful with regard to weight "gain".

It can influence flutter properties.
Forum: RV General Discussion/News 06-18-2020, 08:13 AM
Replies: 8
Views: 2,207
Posted By Marc Bourget
John Thorp was a recognized expert in engine...

John Thorp was a recognized expert in engine installations - since his time serving as Lockheed's "engine liason" with all the WW2 engine manufacturers.

What few people know is that he advised...
Forum: RV General Discussion/News 06-10-2020, 08:29 PM
Replies: 42
Views: 5,113
Posted By Marc Bourget
John Thorp was the first suit that I recall. The...

John Thorp was the first suit that I recall. The builder was flying with two before released for passengers and the rumor/explanation was the battery was improperly secured and moved back in the...
Forum: Traditional Aircraft Engines 06-08-2020, 08:26 AM
Replies: 22
Views: 2,638
Posted By Marc Bourget
I haven't seen this approach before and am...

I haven't seen this approach before and am confused (seriously- not kidding).

It doesn't "fit" with my prior experience.

What is the benefit from blocking cooling air access to the "top" of the...
Forum: RV-12/RV-12iS 06-08-2020, 08:19 AM
Replies: 30
Views: 5,761
Posted By Marc Bourget
I think I'd focus on calling it "vibration"...

I think I'd focus on calling it "vibration" rather than flutter.

Not being picky, but flutter, in airplane context, usually suggests divergent occillation (increasing in amplitude). This appears...
Forum: RV-7/7A 05-31-2020, 08:38 AM
Replies: 10
Views: 1,789
Posted By Marc Bourget
Have you tried a drill slightly larger than the...

Have you tried a drill slightly larger than the hole, and roll it between two fingers as you rock it back and forth?

Sharp drill won't require much pressure. A finger from the other hand near the...
Forum: RV-12/RV-12iS 05-24-2020, 10:39 AM
Replies: 13
Views: 3,659
Posted By Marc Bourget
You see the wrinkling because the skin is flexing...

You see the wrinkling because the skin is flexing in response to the expansion. This minimizes stress on the rivets.
Forum: Tools 05-19-2020, 11:30 AM
Replies: 8
Views: 1,248
Posted By Marc Bourget
DTARM1 said: "I made a box for mine out of OSB...

DTARM1 said: "I made a box for mine out of OSB and fiberglass insulation"

Consider adding a feature to your soundbox.

I quieted a 110dB granulator down to 70 dB using the same approach - but...
Forum: Traditional Aircraft Engines 05-15-2020, 08:20 PM
Replies: 6
Views: 857
Posted By Marc Bourget
I think the O-235 is lighter and may require a...

I think the O-235 is lighter and may require a longer motor mount to maintain W&B range.
Forum: Traditional Aircraft Engines 05-15-2020, 10:13 AM
Replies: 7
Views: 1,071
Posted By Marc Bourget
From what I could see from the pictures . ....

From what I could see from the pictures . . .

Did this happen while the case halves were being separated?

Suggest lightly "Draw file" with a sharp file then debur the edges like normal.

As long as...
Forum: Traditional Aircraft Engines 05-13-2020, 08:59 PM
Replies: 11
Views: 2,232
Posted By Marc Bourget
Supplement to "have to pull a cylinder" If...

Supplement to "have to pull a cylinder"

If you're careful you might be able to un-nut a cylinder and pull it away from the case without removing the piston from the cylinder - take your "peek" at...
Forum: RV General Discussion/News 05-13-2020, 11:55 AM
Replies: 201
Views: 39,480
Posted By Marc Bourget
Bound or was it a low coefficient of friction...

Bound or was it a low coefficient of friction coupled with the mass of the tire?

[true, open question - in consideration of "other factors")
Forum: RV-14 04-25-2020, 02:27 PM
Replies: 8
Views: 2,767
Posted By Marc Bourget
If the previously mentioned approaches don't work...

If the previously mentioned approaches don't work for you.

"Ve half udder vays" :D

During my "apprenticeship" at the Burbank shop, I was prompted to make a couple of bucking bars (1/8" rivets)...
Forum: RV General Discussion/News 04-25-2020, 07:46 AM
Replies: 8
Views: 762
Posted By Marc Bourget
General Observation on #6 screws This standard...

General Observation on #6 screws

This standard has the lowest ratio of outside diameter to root diameter.

Back in the '70's, I was cautioned by guys that worked for Lockheed Vega (prototype dept)...
Forum: Texas (North) 04-20-2020, 05:30 AM
Replies: 7
Views: 794
Posted By Marc Bourget
I assume your speaking of steel? Ron Covell has...

I assume your speaking of steel?

Ron Covell has a video where he bends 1-1/2" steel to a "custom" curve using a template. I watched him do this in person at the Santa Cruz Metal Meet.

FWIW
Forum: RV General Discussion/News 04-09-2020, 06:10 AM
Replies: 11
Views: 1,337
Posted By Marc Bourget
Accessed the link and Mozilla warned me that...

Accessed the link and Mozilla warned me that there's a problem that poses a risk to my security.

Anyone else experience this? My computer date/time is correct.
Forum: RV General Discussion/News 03-24-2020, 07:50 PM
Replies: 5
Views: 1,693
Posted By Marc Bourget
Jeez, what a shame, She'll be so distracted by...

Jeez, what a shame, She'll be so distracted by Sun'nFun!

:D
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