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Search: Posts Made By: Marc Bourget
Forum: RV General Discussion/News 03-24-2020, 07:50 PM
Replies: 5
Views: 1,163
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
Forum: RV-7/7A 03-19-2020, 09:22 AM
Replies: 20
Views: 2,937
Posted By Marc Bourget
Wonder what the disturbed airflow over the tail...

Wonder what the disturbed airflow over the tail with a removed canopy does to landing and low speed operations ???
Forum: RV General Discussion/News 03-15-2020, 09:39 AM
Replies: 16
Views: 2,788
Posted By Marc Bourget
That looks workable with a rubber mallet and a...

That looks workable with a rubber mallet and a "custom" bucking-backing bar for the trailing edge. Use a "fresh" rubber mallet. One that's sat on the bench in the sunlight for awhile will act like...
Forum: RV General Discussion/News 03-15-2020, 09:15 AM
Replies: 10
Views: 644
Posted By Marc Bourget
The steps provided by Carl repeats previous posts...

The steps provided by Carl repeats previous posts from other threads, but I am concerned about any regularly ground drill bit used to drill plexiglass - particularly the "far side" exit. Moreso when...
Forum: RV-6/6A 03-07-2020, 08:21 AM
Replies: 13
Views: 1,542
Posted By Marc Bourget
If you decide to get picky, I think that speed...

If you decide to get picky, I think that speed changes with aircraft weight. Not a lot, but, someone who was more knowlegible and smarter than me convinced me it was worth "tucking in the back of...
Forum: RV Building Tips/Techniques 02-28-2020, 03:16 PM
Replies: 33
Views: 3,382
Posted By Marc Bourget
The expansion coefficient is part of the...

The expansion coefficient is part of the manufacturers data and specification.

Here's something I just copied

Product

Inches/Foot/100 °F
Plexiglas® sheet Aluminum ...
Forum: RV Building Tips/Techniques 02-27-2020, 09:03 AM
Replies: 33
Views: 3,382
Posted By Marc Bourget
Compae the coefficient of expansion of the plexi...

Compae the coefficient of expansion of the plexi with the aluminum (IIRC it's a factor greater than 3) It gets significant as the edge of the canopy grows in length.
Forum: RV General Discussion/News 02-27-2020, 08:54 AM
Replies: 7
Views: 934
Posted By Marc Bourget
If the skin doesn't vibrate in flight, I'd...

If the skin doesn't vibrate in flight, I'd consider ignoring it.

One issue with "fitting" skins with cleecos, is that they aren't accurate positioners.

I was taught by guys who learned their...
Forum: RV General Discussion/News 02-26-2020, 08:59 AM
Replies: 14
Views: 1,163
Posted By Marc Bourget
My impression is that the original prep for the...

My impression is that the original prep for the powder coat was insufficient.

Had a shop two doors down from a Powder Coating business.

Jerry was a great guy. Every stage of his "personal tour"...
Forum: RV Ongoing Maintenance Issues 02-16-2020, 02:19 PM
Replies: 16
Views: 2,517
Posted By Marc Bourget
Isn't the solution for a castellated nut that...

Isn't the solution for a castellated nut that won't "line up" a different washer stack?

Maybe even a custom thickness washer?

FWIW
Forum: RV General Discussion/News 02-16-2020, 02:14 PM
Replies: 11
Views: 1,417
Posted By Marc Bourget
In the 70's I used to get "new" rivets from...

In the 70's I used to get "new" rivets from Fullerton Air Parts. Picked them up on Thursday, as they were the freshest. Would drive well at 60 psi at the gun. Within 3 days, 80 psi and longer...
Forum: RV-7/7A 01-17-2020, 08:01 AM
Replies: 81
Views: 12,787
Posted By Marc Bourget
Talking It was my understanding that various analysis...

It was my understanding that various analysis approaches were "methods" which did only that, "approach" a solution to the issue

The point about "dissuade" was just that. John didn't design a trim...
Forum: RV-7/7A 01-16-2020, 11:50 AM
Replies: 81
Views: 12,787
Posted By Marc Bourget
jrs14855 said: "Any one who intentionally...

jrs14855 said: "Any one who intentionally attempts to fly with a trim tab disconnected is nuts."

Well . . . . From 23.629:

[snip]

(f) Freedom from flutter, control reversal, and divergence up to...
Forum: RV-7/7A 01-16-2020, 07:38 AM
Replies: 81
Views: 12,787
Posted By Marc Bourget
Vne Test Format

I'm not familiar with other threads on this subject, but no mention was made of the suggested flight profile while conducting flutter tests.

John Thorp (no stranger to flutter) recommended (of...
Forum: RV General Discussion/News 01-12-2020, 09:46 AM
Replies: 14
Views: 1,562
Posted By Marc Bourget
End Caps? Why not swedge the ends to a ball, or...

End Caps?

Why not swedge the ends to a ball, or plug it with solid bar at the ID of the tube then "round off"?
Forum: RV General Discussion/News 01-11-2020, 12:19 PM
Replies: 7
Views: 1,027
Posted By Marc Bourget
With lathe access you can create an elegant...

With lathe access you can create an elegant solutions to providing a big boost in accurate hole position transfer.
Forum: RV General Discussion/News 01-11-2020, 12:06 PM
Replies: 14
Views: 1,562
Posted By Marc Bourget
Is this to be used as a "hook" to "store" the...

Is this to be used as a "hook" to "store" the belts when not in use?

If so, I'd say sure. For that use, tubing may be enough ???

I believe my prior bend was for T-6.

My OCD says still check the...
Forum: RV General Discussion/News 01-11-2020, 09:03 AM
Replies: 14
Views: 1,562
Posted By Marc Bourget
I "Like" JRS's comment - Right On! 6061 can be...

I "Like" JRS's comment - Right On!

6061 can be "annealed" but the sharpie and torch technique isn't annealing, it's relief from Work hardening and is sometimes described as "W" temper.

Check the...
Forum: RV General Discussion/News 01-11-2020, 08:43 AM
Replies: 7
Views: 1,027
Posted By Marc Bourget
Match Drilling

I’m assuming you want to locate holes in the Cowl for placement of the fasteners, not vice versa. The technique I propose works either way with a little adjustment.

Good chance for getting an...
Forum: RV-14 01-11-2020, 07:50 AM
Replies: 9
Views: 1,069
Posted By Marc Bourget
Countersinking thin sheet

Proper countersinking technique is performed in sheet thick enough to leave a "barrel". Knife edge at the bottom of the hole is a no-no.

My AV and SnF forum and reference materials are currently...
Forum: RV General Discussion/News 01-03-2020, 09:00 AM
Replies: 21
Views: 2,166
Posted By Marc Bourget
These tips resemble the Horner Tips produced in...

These tips resemble the Horner Tips produced in the mid '70's.

While visiting John Thorp at Whitemans Field, Burbank, I listened to a conversation between John and a Bonanza owner, bragging about...
Forum: RV Building Tips/Techniques 12-28-2019, 08:49 AM
Replies: 18
Views: 2,013
Posted By Marc Bourget
It's not all about saving weight. Don't forget...

It's not all about saving weight. Don't forget the stiffness factor.

Part of the design component and probably the major purpose is to avoid a sudden, significant, change in stiffness - generating...
Forum: RV Building Tips/Techniques 12-26-2019, 06:57 AM
Replies: 18
Views: 2,013
Posted By Marc Bourget
Milling the skins would be lots of work. John...

Milling the skins would be lots of work.

John Thorp once described a method of reducing skin thickness for the Wind Derringer. The skins were "chemically milled" by dipping the aluminum in an acid...
Forum: RV Building Tips/Techniques 12-24-2019, 01:05 PM
Replies: 18
Views: 2,013
Posted By Marc Bourget
I picked up an engineering textbook from Northrup...

I picked up an engineering textbook from Northrup Factory published in 1942. Detail Design and Engineering. Stiffener taper was explained in the best practices section.

The book is currently...
Forum: RV Building Tips/Techniques 12-23-2019, 07:55 AM
Replies: 18
Views: 2,013
Posted By Marc Bourget
Failing to reduce the height also presents a...

Failing to reduce the height also presents a stress concentration situation.
Forum: RV-14 12-23-2019, 07:49 AM
Replies: 30
Views: 3,075
Posted By Marc Bourget
Useful in many areas when you're laying out and...

Useful in many areas when you're laying out and riveting.

Cleecos aren't the best locating device. In a few spots best calculated to maintain alignment consider drilling with a fractional drill...
Forum: RV-14 12-12-2019, 07:17 AM
Replies: 10
Views: 1,289
Posted By Marc Bourget
Best approach to avoid the hardened material and...

Best approach to avoid the hardened material and Chernobyling your drill bit is to understand you add pressure sufficient to constantly undercut the surface of the hardened material made by the...
Forum: Traditional Aircraft Engines 11-02-2019, 06:14 AM
Replies: 34
Views: 9,017
Posted By Marc Bourget
I couldn't open the photos but will search for...

I couldn't open the photos but will search for and check the reference.

IIRC, test clubs provided the important benefit of reducing the effect of harmonics in the crank if ran "unloaded"
Forum: RV-9/9A 10-24-2019, 05:39 AM
Replies: 11
Views: 1,128
Posted By Marc Bourget
Bill R said: "You want to give the air space to...

Bill R said: "You want to give the air space to slow down before going past the cylinders. "

Please clarify that statement as I understand attaining "Reynolds Number Velocity" is essential to...
Forum: RV-4 10-16-2019, 07:10 AM
Replies: 18
Views: 1,993
Posted By Marc Bourget
Guys, They did a lot of experimentation on this...

Guys,

They did a lot of experimentation on this point at NACA Langley.

Try TR-496 and its extension to trim tabs in ailerons TR-736 and TR-685

Specific to location of balance point, Try NACA...
Forum: RV-14 10-12-2019, 07:53 AM
Replies: 13
Views: 2,120
Posted By Marc Bourget
I consider a skin that "oil cans" to be in an...

I consider a skin that "oil cans" to be in an indeterminate or reversible configuration.

Depending on access to the inside. . .

It would take careful inspection and judgment by one with some...
Forum: RV General Discussion/News 10-05-2019, 11:17 AM
Replies: 25
Views: 14,685
Posted By Marc Bourget
Errata explanation I read the report...

Errata explanation

I read the report (http://www.n91cz.com/InductionSizing...izing_rev0.pdf) and was initially confused.

He states earlier in the report to divide the volume derived from...
Forum: RV-6/6A 09-30-2019, 02:53 PM
Replies: 11
Views: 1,157
Posted By Marc Bourget
Red face Wondering why you have to "slam" the throttle on...

Wondering why you have to "slam" the throttle on T/O on a routine basis (besides the fact that it's FUN! :D)

I learned my lesson on this at an early age, inspecting a prop that had somehow run over...
Forum: RV General Discussion/News 09-29-2019, 05:29 PM
Replies: 36
Views: 4,005
Posted By Marc Bourget
All sorts of compromises must be addressed...

All sorts of compromises must be addressed here.

If he bottom of the "D" inlet is properly shaped, it might be advantageous to tilt the inlet slightly downward - seeking to obtain the best Delta P...
Forum: RV General Discussion/News 09-29-2019, 10:31 AM
Replies: 45
Views: 9,414
Posted By Marc Bourget
I seem to recall a momentary incident where a...

I seem to recall a momentary incident where a T-18 pilot developed blisters on his palm that was explained as caused by a flutter incident.

Flutter is an aero-elastic condition, it's hard to...
Forum: RV General Discussion/News 09-24-2019, 09:22 PM
Replies: 16
Views: 2,159
Posted By Marc Bourget
Every time I come across a prop strike I get...

Every time I come across a prop strike I get concerned.

Friend was a 38 yr Mechanical Engineer for various OEM's and was on the "core" design team for several engines. Also a pilot we discussed the...
Forum: Alternative Engines 09-14-2019, 04:02 PM
Replies: 42
Views: 16,528
Posted By Marc Bourget
I've followed the engine from the inception and...

I've followed the engine from the inception and spoke with the designer. One of the original arguments advanced to justify the heavier engine is that you could accept less fuel load because of the...
Forum: RV Photo/Video URLs 08-07-2019, 03:39 PM
Replies: 8
Views: 1,933
Posted By Marc Bourget
control said: "I would have expected more...

control said: "I would have expected more turbulence"

I don't think the exhaust has the density/mass to oppose the slipstream and generate significant turbulence.]

FWIW
Forum: Fuel Injection Systems 08-06-2019, 02:46 PM
Replies: 7
Views: 1,227
Posted By Marc Bourget
Was that 190 PSI or did you mean 190K PSI...

Was that 190 PSI or did you mean 190K PSI material?

(I hate it when my aged fingers drop important keystrokes!) :)
Forum: RV General Discussion/News 08-02-2019, 09:12 AM
Replies: 69
Views: 17,015
Posted By Marc Bourget
Clicked on the link in the first post and got the...

Clicked on the link in the first post and got the following:

"Sorry, the page you requested does not exist (anymore)."
Forum: RV Building Tips/Techniques 07-30-2019, 04:40 PM
Replies: 11
Views: 1,665
Posted By Marc Bourget
The two skins are, say, 1/16" apart. You...

The two skins are, say, 1/16" apart. You slightly "tickle" the rivet gun and it simply swells or fattens the shaft of the rivet sufficient to create some drag between the shaft and the hole of the...
Forum: RV Building Tips/Techniques 07-27-2019, 02:31 PM
Replies: 11
Views: 1,665
Posted By Marc Bourget
Never thought to use the windshield hose, as I...

Never thought to use the windshield hose, as I was taught a "draw" technique by a WWII Lockheed worker.

Which is . . . to slightly swell the shank of the rivet to increase it's diameter. The...
Forum: Electrical Systems 07-14-2019, 04:18 PM
Replies: 9
Views: 779
Posted By Marc Bourget
Maybe put some "tattle tale" paint and check...

Maybe put some "tattle tale" paint and check often ???
Forum: Traditional Aircraft Engines 07-04-2019, 07:47 AM
Replies: 4
Views: 596
Posted By Marc Bourget
Use the "original" baffle kit. An increase in...

Use the "original" baffle kit.

An increase in displacement via a "stroker" crank typically uses the original cylinder assembly.

Generally, a longer stroke will require either a shorter connecting...
Forum: Electrical Systems 07-04-2019, 07:39 AM
Replies: 2
Views: 536
Posted By Marc Bourget
While parallel to your question, it's worth...

While parallel to your question, it's worth reviewing the following:

I was taught that you size the wire (conductor) according to the load you wish to satisfy and then size the circuit breaker to...
Forum: Traditional Aircraft Engines 06-22-2019, 11:53 AM
Replies: 45
Views: 9,757
Posted By Marc Bourget
Dr. Phil said: "Am I to assume that the 13 row...

Dr. Phil said: "Am I to assume that the 13 row Niagara oil cooler purchased from Van’s is a piece of junk?"

I'm not familiar with you, but reading the above made me question your understanding of...
Forum: Job Board 06-05-2019, 04:38 PM
Replies: 4
Views: 1,590
Posted By Marc Bourget
I had the privilege of a "behind the scenes" tour...

I had the privilege of a "behind the scenes" tour some years back, given by F. Steinle (SP?)

It was the experience of a lifetime, a real "bucket list" item. Being a "builder" I found the NFAC more...
Forum: RV General Discussion/News 05-31-2019, 09:32 PM
Replies: 32
Views: 6,439
Posted By Marc Bourget
I remember reading about a pair of doors in the...

I remember reading about a pair of doors in the upper plenum that were hinged. On the ground they would open, but in flight the dynamic pressure would find them closed.

Never saw a picture, but...
Forum: RV-7/7A 05-27-2019, 08:49 AM
Replies: 7
Views: 1,262
Posted By Marc Bourget
Keep in mind, again depending on placement (and...

Keep in mind, again depending on placement (and what's behind it), you can always find a need for an additional firewall penetration in the future (testing baffle performance, etc) so consider...
Forum: Traditional Aircraft Engines 05-22-2019, 07:33 AM
Replies: 21
Views: 1,870
Posted By Marc Bourget
Mark W said: "In the air conditioning heat...

Mark W said: "In the air conditioning heat exchange world i.e. coil design, I have always been told that the majority of the heat exchange takes place in the edge of the fin and not the surface of...
Forum: Traditional Aircraft Engines 05-21-2019, 07:46 AM
Replies: 21
Views: 1,870
Posted By Marc Bourget
Bill said: "I have come to the conclusion that...

Bill said: "I have come to the conclusion that the flow through heads and barrels is controlled by the exit gap on the bottom."

I believe there is a NACA report that represents the exit gap is...
Forum: Traditional Aircraft Engines 05-18-2019, 03:27 PM
Replies: 3
Views: 804
Posted By Marc Bourget
RV74me said: "What do you guys think? Taking...

RV74me said: "What do you guys think?

Taking the temp of an assembly that is so "varied" in conformation can be problematical.

Understand that I speak from the perspective of having read a NACA...
Forum: RV General Discussion/News 04-21-2019, 11:06 AM
Replies: 10
Views: 1,086
Posted By Marc Bourget
Just enough spring pressure to prevent the joint...

Just enough spring pressure to prevent the joint from separating under the force of backpressure, which will be pretty low.

Add a little bit for "mother" to prevent excess chaffing from vibration
Forum: RV General Discussion/News 04-13-2019, 01:08 PM
Replies: 45
Views: 9,414
Posted By Marc Bourget
Guys, frequency issues are also a factor. ...

Guys, frequency issues are also a factor.

Weight placement and its overall distribution can be a factor.

Interesting thing about adding trim tabs not included in original is that few, if any,...
Forum: RV Building Tips/Techniques 03-16-2019, 11:41 AM
Replies: 13
Views: 1,768
Posted By Marc Bourget
If you are speaking of standard AD rivets, I...

If you are speaking of standard AD rivets, I would look first to your dimpling technique.

When I first started, wary of the "softness" of the Alu, I was always under forming the dimple. You have...
Forum: RV General Discussion/News 02-24-2019, 08:26 AM
Replies: 11
Views: 1,131
Posted By Marc Bourget
I'm curious about this as I didn't think much in...

I'm curious about this as I didn't think much in the way of volume flows through the Pitot "side". Maybe the static because of some instrument bleed, but I wonder if "design" or "configuration" of...
Forum: RV-4 02-09-2019, 08:08 AM
Replies: 24
Views: 3,471
Posted By Marc Bourget
Check and then monitor your temps. Don't get too...

Check and then monitor your temps. Don't get too high. Once it flows well, stabilize the heat
Forum: RV-10 02-07-2019, 08:23 AM
Replies: 13
Views: 1,657
Posted By Marc Bourget
Point to ponder. The struts and seals are...

Point to ponder. The struts and seals are purposed application - unlike accessories selected from catalogs or copied from this forum.

Not weighing in one way or the other, just adding...
Forum: Safety 02-04-2019, 09:17 AM
Replies: 47
Views: 5,214
Posted By Marc Bourget
All well and good but survivability is increased...

All well and good but survivability is increased by more attention to restraints.

I recall a 78 yr old lady who expired in a relatively low speed auto accident because of Atherosclerosis. The...
Forum: RV-4 01-29-2019, 08:44 AM
Replies: 4
Views: 756
Posted By Marc Bourget
Talking Quick rule of thumb for future reference - for...

Quick rule of thumb for future reference - for the less knowledgeable.

Breakers sized for (to protect) the conductor.

Conductors are sized for the load.

Why the difference here?

Motors have a...
Forum: RV-7/7A 01-27-2019, 10:07 AM
Replies: 13
Views: 2,216
Posted By Marc Bourget
Bill, Was there a reason, besides aesthetics, to...

Bill,

Was there a reason, besides aesthetics, to using flush rivets?
Forum: Propellers 01-27-2019, 10:03 AM
Replies: 71
Views: 16,558
Posted By Marc Bourget
Can you provide a fairly accurate measurement of...

Can you provide a fairly accurate measurement of the position of the crack in relation to the overall length of the blade (and in respect to the length outside of the hub) ?

Wonder if the crack...
Showing results 1 to 62 of 243

 
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