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Search: Posts Made By: scsmith
Forum: Propellers Today, 08:37 PM
Replies: 7
Views: 264
Posted By scsmith
The IO-360-A1A is not. The IO-360-A3B6 is.

The IO-360-A1A is not. The IO-360-A3B6 is.
Forum: Safety 02-21-2021, 08:52 PM
Replies: 46
Views: 2,696
Posted By scsmith
That's interesting Skylor. This suggests there...

That's interesting Skylor. This suggests there is a check-valve feature in the governor that prevents or restricts bleed back of the oil pressure.

My old MT governor gave control to very low RPM,...
Forum: RV General Discussion/News 02-21-2021, 08:44 PM
Replies: 48
Views: 2,986
Posted By scsmith
I will do my darnedest to make it to OSh this...

I will do my darnedest to make it to OSh this year... My first year. And yes, assuming I make it, I will be there for the social.

I get my second shot in two weeks.
Forum: Safety 02-21-2021, 01:36 PM
Replies: 46
Views: 2,696
Posted By scsmith
For a given pitch setting, the prop will spin...

For a given pitch setting, the prop will spin fastest when no work is being extracted from it. Any braking torque from turning the dead engine will slow the prop down. So your observation of the...
Forum: Safety 02-20-2021, 02:44 PM
Replies: 46
Views: 2,696
Posted By scsmith
Interesting. OK. I was wrong.

Interesting. OK. I was wrong.
Forum: RV General Discussion/News 02-19-2021, 04:03 PM
Replies: 20
Views: 1,342
Posted By scsmith
It is interesting that you point this out. Aero...

It is interesting that you point this out. Aero and propulsion folks that work in the Imperial units system (ft, lb_f, sec) cling to that unit system with the 'excuse' that we have more intuition...
Forum: RV General Discussion/News 02-19-2021, 02:08 PM
Replies: 20
Views: 1,342
Posted By scsmith
Because the atmosphere is so thin, you can not...

Because the atmosphere is so thin, you can not get gentle descent rates with parachutes alone. well, reasonably sized ones anyway.
The early rovers dropped onto the surface inside a beach ball. When...
Forum: RV General Discussion/News 02-19-2021, 02:47 AM
Replies: 20
Views: 1,342
Posted By scsmith
More about ARES

I know this is pretty far from RV related, so if a moderator wants to take it down, I would understand. But I think people would find it interesting.

If you want to learn more about the ARES Mars...
Forum: RV-7/7A 02-19-2021, 02:05 AM
Replies: 20
Views: 1,760
Posted By scsmith
Gun ports

Spitfires used to tape over the gun ports in the leading edge with red tape.

Back to the issue at hand, the only whistle or buzz I have had is when the rubber seal on the wing root fairing has had...
Forum: RV General Discussion/News 02-18-2021, 08:27 PM
Replies: 20
Views: 1,342
Posted By scsmith
YAY!

I worked on a very early Mars airplane design activity, and then worked on the ARES Mars airplane, a project led from NASA Langley in 2003-2004, in competition for the 2007 Mars Scout mission. We...
Forum: Fuel Injection Systems 02-16-2021, 05:55 PM
Replies: 25
Views: 3,223
Posted By scsmith
DanH's idea is to reduce the internal volume as...

DanH's idea is to reduce the internal volume as much as possible. Just changing the ends doesn't do it. Even if the -2 line is pricey, a bunch of us might happily pay it to avoid this cloud hanging...
Forum: RV General Discussion/News 02-16-2021, 05:45 PM
Replies: 19
Views: 1,212
Posted By scsmith
Alaska Airlines flies into Medford, Oregon. Any...

Alaska Airlines flies into Medford, Oregon. Any time you like, when the weather is good. I'll pick you up at Millionaire FBO. I'm assuming you work for Alaska? If so, you could even do it during a...
Forum: RV General Discussion/News 02-16-2021, 05:43 PM
Replies: 19
Views: 1,212
Posted By scsmith
Especially since he lives in Alaska!

Especially since he lives in Alaska!
Forum: Safety 02-13-2021, 08:02 PM
Replies: 46
Views: 2,696
Posted By scsmith
The zero-thrust glide data is of great academic...

The zero-thrust glide data is of great academic interest for evaluating the aerodynamic performance of the airframe.

But it is not at all useful for determining engine-out glide ratio, or best...
Forum: Safety 02-13-2021, 07:58 PM
Replies: 46
Views: 2,696
Posted By scsmith
Hmmm. Remember we are talking about a dead...

Hmmm. Remember we are talking about a dead engine -- ignition off.

On an idealized p-V diagram, regardless of throttle position, the compression and power strokes absorb no net work. Just an...
Forum: Tools 02-13-2021, 02:08 PM
Replies: 11
Views: 374
Posted By scsmith
Are you asking about manual pullers or pneumatic...

Are you asking about manual pullers or pneumatic pullers?

I would think if you are going to build an RV-12, you will be well-advised to get a pneumatic puller. They vary significantly in price and...
Forum: Aircraft Camping 02-13-2021, 02:02 PM
Replies: 13
Views: 977
Posted By scsmith
In my ongoing attempts to keep the record...

In my ongoing attempts to keep the record straight, the dry lakebed is officially known as Flannigan Dry Lake.



I would think that spraying ACF-50 would be a disaster, just an oily coating that...
Forum: RV General Discussion/News 02-12-2021, 03:17 PM
Replies: 6
Views: 540
Posted By scsmith
Here you...

Here you go.

https://arc.aiaa.org/doi/pdf/10.2514/3.45828

Looks like it costs $25 for permanent access to the pdf. In the old days, you would get a paper "pre-print" for that price.
Forum: Safety 02-11-2021, 08:00 PM
Replies: 46
Views: 2,696
Posted By scsmith
This would be true if you had an electric power...

This would be true if you had an electric power plant that added no additional windmill drag. But the added windmill drag will result in a best power-off glide speed a fair bit slower than the...
Forum: VAF Classifieds (posts in here deleted after 30 days) 02-10-2021, 10:16 PM
Replies: 9
Views: 568
Posted By scsmith
Sent you a PM

Sent you a PM
Forum: RV-8/8A 02-10-2021, 08:22 PM
Replies: 12
Views: 1,265
Posted By scsmith
This was going to be my recommendation for an...

This was going to be my recommendation for an improvement. I think regardless of exhaust, there is a tendency for that panel to oil-can. Even more so on the RV-7, I've seen it.
Forum: Safety 02-10-2021, 12:00 PM
Replies: 46
Views: 2,696
Posted By scsmith
Skylor, It is true that for minimum altitude loss...

Skylor,
It is true that for minimum altitude loss in a turn, you should fly at minimum sink speed for that loading (W/cos B), rather than best L/D speed. But at the elevated loading, the polar...
Forum: RV General Discussion/News 02-10-2021, 01:20 AM
Replies: 21
Views: 1,753
Posted By scsmith
AGAIN...I quoted directly from the article: it...

AGAIN...I quoted directly from the article:
it says "A crossover exhaust joins the headers of cylinders whose firings occur 180 crankshaft degrees apart. " which is incorrect.
Forum: Safety 02-09-2021, 05:46 PM
Replies: 46
Views: 2,696
Posted By scsmith
Bob, with the throttle open, the intake strokes...

Bob,
with the throttle open, the intake strokes pull a lot of air in, and the exhaust strokes pump a lot of air out. That is doing a lot of work, which the engine absorbs from the prop. With the...
Forum: Safety 02-09-2021, 01:51 PM
Replies: 46
Views: 2,696
Posted By scsmith
I did 360-degree turns starting at 2000 ft over...

I did 360-degree turns starting at 2000 ft over mid-field of a long runway, at idle power (gives 600 RPM on the ground, obviously higher in flight). Unable to adjust c/s pitch at low RPM with my...
Forum: Traditional Aircraft Engines 02-09-2021, 12:42 PM
Replies: 23
Views: 964
Posted By scsmith
The angle-valve engines are 8.7 CR, which...

The angle-valve engines are 8.7 CR, which definitely aggravates detonation. IO-360A engines were data-plate timed at either 20 or 25 BTDC depending on installation. I run mine at 25, operating from...
Forum: Traditional Aircraft Engines 02-08-2021, 09:54 PM
Replies: 23
Views: 964
Posted By scsmith
For those that are following along, what DanH...

For those that are following along, what DanH means is that the 28" MAP data does not go lean enough to show a peak EGT, but it is 'suggested' where that peak is. So you can see where the detonation...
Forum: Traditional Aircraft Engines 02-08-2021, 01:03 PM
Replies: 23
Views: 964
Posted By scsmith
DanH, This performance chart is for "worst case"...

DanH, This performance chart is for "worst case" in most respects, but only 26" MAP. What does the detonation margin look like at 30" MAP?
Forum: Traditional Aircraft Engines 02-08-2021, 12:44 PM
Replies: 23
Views: 964
Posted By scsmith
Note that the IO-390 usually installs an...

Note that the IO-390 usually installs an FM-200.

Bob Mills took an RSA-5 (same size as an FM-150?) off of his IO-540 and installed an FM-300 with a very noticeable increase in power, reduction in...
Forum: RV General Discussion/News 02-08-2021, 01:57 AM
Replies: 21
Views: 1,753
Posted By scsmith
Yes, the article did seem to make a good case for...

Yes, the article did seem to make a good case for 4-into-1 systems. There are other advantages too. DanH is thorough enough that I imagine he had seen this article in 1997 and may have played a...
Forum: RV General Discussion/News 02-08-2021, 01:28 AM
Replies: 21
Views: 1,753
Posted By scsmith
The only experience I have with nozzles was on a...

The only experience I have with nozzles was on a turbocharged engine. A nozzle at the exit raises the turbo back pressure, which raises the turbo inlet pressure for the same boost (the turbo was...
Forum: Traditional Aircraft Engines 02-08-2021, 01:20 AM
Replies: 23
Views: 964
Posted By scsmith
I think your fuel flow is too low too, but...

I think your fuel flow is too low too, but perhaps by even more than suggested by RV10inOz. My IO-360-A (200 hp) pulls almost 20 gph at sea level takeoff power, 150F ROP.

So if you have a 260 hp...
Forum: RV General Discussion/News 02-07-2021, 07:07 PM
Replies: 21
Views: 1,753
Posted By scsmith
It is pretty clear, it says "A crossover exhaust...

It is pretty clear, it says "A crossover exhaust joins the headers of cylinders whose firings occur 180 crankshaft degrees apart. " which is incorrect. I'm wondering if the majority of...
Forum: RV General Discussion/News 02-07-2021, 05:23 PM
Replies: 21
Views: 1,753
Posted By scsmith
Another error! "this results in the valves...

Another error! "this results in the valves opening twice during the four-stroke cycle" is wrong. Because the cam turns at half the crank speed, each valve opens ONCE for each four-stroke cycle,...
Forum: RV General Discussion/News 02-07-2021, 04:45 PM
Replies: 21
Views: 1,753
Posted By scsmith
I fixed the link to the CAFE article. On...

I fixed the link to the CAFE article.

On Vetterman's web site, I checked a Mac, an iPad, and a HP windows machine. It must be my ISP blocking because of an unrecognized security certificate or...
Forum: RV General Discussion/News 02-07-2021, 04:43 PM
Replies: 21
Views: 1,753
Posted By scsmith
Yes, you are correct. I edited my original...

Yes, you are correct. I edited my original post....

thanks.
Forum: RV General Discussion/News 02-07-2021, 04:24 PM
Replies: 21
Views: 1,753
Posted By scsmith
Exhaust system performance

Larry DeCamp's recent thread about finding intake leaks contained an interesting reference provided by Kyle Boatright on exhaust system performance, written by the CAFE...
Forum: RV-8/8A 02-05-2021, 07:16 PM
Replies: 11
Views: 989
Posted By scsmith
I don't know if the Tom Clark fastback with...

I don't know if the Tom Clark fastback with slider is available anymore? I was figuring if I do a fastback on my next one, I will have to roll my own.
Forum: RV-8/8A 02-04-2021, 08:36 PM
Replies: 11
Views: 989
Posted By scsmith
You might consider the newer IO-390-EXP 119...

You might consider the newer IO-390-EXP 119 engine. A bit more Hp, a bit lighter.

And I would recommend hard-mounting the oil cooler on the firewall with an appropriate bracket, and a fiberglass...
Forum: RV Building Tips/Techniques 02-03-2021, 02:27 PM
Replies: 35
Views: 4,116
Posted By scsmith
One of the advantages I found to using the...

One of the advantages I found to using the DecalPro system was that you don't have to plan everything out for sure the way everything is going to be all at once and send off to a vendor.

You can...
Forum: RV Building Tips/Techniques 02-02-2021, 03:38 PM
Replies: 53
Views: 7,231
Posted By scsmith
Yes, it would be fairly straightforward to make...

Yes, it would be fairly straightforward to make this switch. I think they are 8-32, but don't trust me, check the plans.
Forum: RV Building Tips/Techniques 02-01-2021, 07:49 PM
Replies: 53
Views: 7,231
Posted By scsmith
Please see post #16. Eleven+ years and no leaks.

Please see post #16. Eleven+ years and no leaks.
Forum: Traditional Aircraft Engines 01-31-2021, 05:58 PM
Replies: 13
Views: 777
Posted By scsmith
My angle-valve IO-360 has idle set at about 600. ...

My angle-valve IO-360 has idle set at about 600. With the very light WW prop, it is a little bit lopey, but OK.
Forum: RV-8/8A 01-26-2021, 01:46 PM
Replies: 7
Views: 389
Posted By scsmith
My kit was pre-matched hole, like yours. Looking...

My kit was pre-matched hole, like yours. Looking at the new drawing (68) the parts sure look the same but hard to say what tweaks they did when they made the new matched hole parts. It also seems...
Forum: Safety 01-26-2021, 01:04 PM
Replies: 18
Views: 2,084
Posted By scsmith
They are exploiting the margins, but many of them...

They are exploiting the margins, but many of them have also had structural mods - but probably not all. Most common are added stiffness in the fin and rudder. They are the test pilot for their...
Forum: Safety 01-26-2021, 12:57 PM
Replies: 18
Views: 2,084
Posted By scsmith
I do not believe this is true. Loading a...

I do not believe this is true. Loading a surface does not change its stiffness. Elastic materials are linear. The natural frequencies of the modes won’t change appreciably. AND actually if you...
Forum: RV Building Tips/Techniques 01-26-2021, 01:36 AM
Replies: 14
Views: 1,157
Posted By scsmith
If it is out of the sun but in the prop wash, it...

If it is out of the sun but in the prop wash, it will most likely get some diluted exhaust effect. There is a fair bit of mixing. There is also the higher velocity of the slip stream increasing the...
Forum: RV-8/8A 01-26-2021, 01:27 AM
Replies: 7
Views: 389
Posted By scsmith
One thing I did that I am glad I did was...

One thing I did that I am glad I did was reinforce the front lip of the F-880AAp with a piece of angle under the lip. No one will ever see it or notice it but that seat edge takes all manner of...
Forum: RV General Discussion/News 01-25-2021, 10:40 PM
Replies: 11
Views: 5,849
Posted By scsmith
Hexavalent chromium

Thank you Larry for mentioning proper disposal. Folks, this is the stuff that made Erin Brokovich rich, P,G,&E poor, and the whole town of Hinkley, CA sick with all manor of debilitating disorders....
Forum: Nosewheel vs. Tailwheel 01-25-2021, 02:30 PM
Replies: 23
Views: 7,437
Posted By scsmith
I just want to amplify DanH’s point about brakes....

I just want to amplify DanH’s point about brakes.

There was a mishap discussion recently in one of the flying magazines. Improper use of the brakes. I don’t remember the details of the mishap,...
Forum: Safety 01-25-2021, 02:12 PM
Replies: 18
Views: 2,084
Posted By scsmith
V_ne is set by demonstrating a maximum speed that...

V_ne is set by demonstrating a maximum speed that is flutter-free and then reducing that by 15%. By test or analysis they may have a good idea of the true flutter speed and then demonstrate a...
Forum: Alternative Engines 01-25-2021, 01:23 PM
Replies: 52
Views: 3,133
Posted By scsmith
Motors

It is tough to get the power out of electric motors at the RPM we need. Out-runner motors run slower but still want to turn faster than we would like.

Gear boxes are heavy.

And cooling. Don’t...
Forum: Alternative Engines 01-25-2021, 12:58 PM
Replies: 52
Views: 3,133
Posted By scsmith
A few points to add

Just a few points on aspects people have mentioned:

Power is constant with altitude but thrust is not. As TAS increases for the same IAS, the thrust drops off. P=T*V Still, the performance...
Forum: Tools 01-24-2021, 06:21 PM
Replies: 9
Views: 888
Posted By scsmith
I'm pretty sure mine are made from 17-4 PH...

I'm pretty sure mine are made from 17-4 PH age-hardening stainless steel.
It is hardened to H900 by simply aging in an oven at 900F for 3 hrs, then air cooled. It is Rockwell C43 at that point, and...
Forum: RV-8/8A 01-20-2021, 02:54 PM
Replies: 12
Views: 1,159
Posted By scsmith
Plan Gotchas

Back to the plan gotchas rather than rivet hole preparation,

These apply to the kits before the matched-hole fuselage, and may or may not apply to the -1 matched hole fuselage kit - I don't know if...
Forum: Electrical Systems 01-16-2021, 06:55 PM
Replies: 34
Views: 2,919
Posted By scsmith
I agree. Especially something like lights. Not...

I agree. Especially something like lights. Not going to experience a mysterious transient and continue to function if a new fuse was installed.
Forum: RV-8/8A 01-16-2021, 05:14 PM
Replies: 12
Views: 1,159
Posted By scsmith
I know of two that I would add if someone wants...

I know of two that I would add if someone wants to start such a permanent thread.
Forum: RV-6/6A 01-16-2021, 05:11 PM
Replies: 17
Views: 2,369
Posted By scsmith
Titanium is heavier than aluminum. You won't...

Titanium is heavier than aluminum. You won't save weight by replacing aluminum skins with titanium skins. You will however be able to keep your skin on should you exceed Mach 2.4
Forum: Electrical Systems 01-16-2021, 05:09 PM
Replies: 34
Views: 2,919
Posted By scsmith
fuses

One thing to keep in mind about fuses:

FAR 91.205 (c) (6) requires that a set of spare fuses, or three of each size fuse, be carried, accessible to the pilot in flight.

Presumably the fuse holder...
Forum: RV Building Tips/Techniques 01-16-2021, 02:27 PM
Replies: 21
Views: 3,671
Posted By scsmith
Yes, true! Also remember that in many places,...

Yes, true!

Also remember that in many places, the screws are supposed to carry shear through an assembly of parts, and it does this by bearing on the sides of the hole. If you open up the clearance...
Forum: Fuel Injection Systems 01-15-2021, 10:55 PM
Replies: 6
Views: 601
Posted By scsmith
Cylinder temps are complex to interpret because...

Cylinder temps are complex to interpret because they are a combination of mass flow (power) and cooling variation. It is hard to sort out which is which. For example, my cylinder #2 runs the...
Forum: RV Building Tips/Techniques 01-15-2021, 07:15 PM
Replies: 21
Views: 3,671
Posted By scsmith
I've never found one that was not threaded. If I...

I've never found one that was not threaded. If I did, I would catch it during my install process because I use a short screw with a jam nut on it as kind of a holder, assures that it is centered in...
Forum: Aircraft Camping 01-13-2021, 01:58 PM
Replies: 75
Views: 35,915
Posted By scsmith
I might be up for it this fall. If you zoom in...

I might be up for it this fall.

If you zoom in on the Google Maps satellite image, you can see the annual Willamette glider camp out in progress. On the west edge near the hot spring. What are the...
Forum: Safety 01-12-2021, 10:32 PM
Replies: 7
Views: 1,334
Posted By scsmith
Yes, it contains hexavalent chromium, which is...

Yes, it contains hexavalent chromium, which is really toxic and causes a whole laundry list of maladies in humans and many other living things. It is the stuff that got into the ground water in...
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