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PakoAry
08-06-2007, 12:53 PM
Hello bombers out there!

What would be the typical velocity range (IAS) for level bombing?

I know this sort of question can produce many "I usually bomb from xxx at yyy mph" or "depends on hte plane"... My idea is to find out the usual IAS range people bomb (ie: B-25 150mph to 200 mph).

PakoAry
08-06-2007, 12:53 PM
Hello bombers out there!

What would be the typical velocity range (IAS) for level bombing?

I know this sort of question can produce many "I usually bomb from xxx at yyy mph" or "depends on hte plane"... My idea is to find out the usual IAS range people bomb (ie: B-25 150mph to 200 mph).

Crash_Moses
08-06-2007, 01:00 PM
Oho! Are you in luck... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Click the link in my sig...any questions just post back.

S!

PakoAry
08-06-2007, 03:04 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Oho! Are you in luck... </div></BLOCKQUOTE>

Unquestionably I am. You guys are dealing with bombers for ages and the fine work found in your bombing guides and tutorials reflect the effort and time invested there. I'm glad my post caught attention of one of the experts... :-)

I've read the guides in M4T (such as yours Crash_Moses congratulations, great job) and noticed that they tend to fix a speed (TAS or IAS depending on the author) and assemble the data from there. That make complete sense once the tables were composed empirically and, as we all know, it involves a lot of testing and tweaking.

I've also noticed that the speeds are not to far from the cruise speed of the a/c. The PBJ, by Moses, is an exception but this is explained by his "method behind the madness" where he read TAS from the no-cockpit view for better accuracy. Therefore, he has close to cruise speed at ground level and lower IAS.

I'm not sure if you guys have dealt with this before or even find this useful anyhow, but I was thinking about finding the limits for level bombing such as:
Plane (IAS):
B-XX 200 240 mph, optimum 230 @ 12000ft
B-YY 180 220 mph, optimum 200 @ 15000ft

I believe the lower IAS would be determined by the capacity to fly level with a particular payload.
The upper, by the max speed reached, level, with that same payload.

Any thoughts?

Has anyone done that already?

Crash_Moses
08-06-2007, 06:51 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I believe the lower IAS would be determined by the capacity to fly level with a particular payload.
The upper, by the max speed reached, level, with that same payload. </div></BLOCKQUOTE>

Yup. 100% true. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I'm not sure if you guys have dealt with this before or even find this useful anyhow, but I was thinking about finding the limits for level bombing such as:
Plane (IAS):
B-XX 200 240 mph, optimum 230 @ 12000ft
B-YY 180 220 mph, optimum 200 @ 15000ft
</div></BLOCKQUOTE>

So, you're thinking of a chart that gives a range of allowable speeds at a given altitude? Sort of like, "Your IAS cannot exceed or fall below this range in order to level bomb with any kind of accuracy."

Unfortunately the bombsight has a small bug in the accuracy of the TAS and/or in the bombsight angle. The discrepency is around 10% but varies depending on altitude, speed, etc.

It's been argued that this is an error in translating KPH to MPH (not true...I've looked hard and can find no correlation between the two) or possibly has been purposly inserted to make bombing accuracy historically accurate.

I dunno which is the case but this discrepency is why I created my bombing my bombing guide. I wanted to create a hyper-accurate bombing table for pinpoint wholesale destruction that factored the bug out of the picture.

I have to admit though, I haven't tested this since 1946 came out as I've been enamored with the SBD of late. Now I'm curious...

Regardless, my tables certainly aren't required in order to succesfully level bomb and I can't see that another table containing good general bombsight data would be a bad thing. Not a bad thing at all. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

I highly recommend this training video by Joe90.

http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/1101043355

S!

PakoAry
08-07-2007, 12:50 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">So, you're thinking of a chart that gives a range of allowable speeds at a given altitude? Sort of like, "Your IAS cannot exceed or fall below this range in order to level bomb with any kind of accuracy." </div></BLOCKQUOTE>

Exactly. The good thing is that since it's IAS it is sort of the same for every altitude.

What I would do is to find the upper and lower limits as stated in:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> I believe the lower IAS would be determined by the capacity to fly level with a particular payload.
The upper, by the max speed reached, level, with that same payload. </div></BLOCKQUOTE>

and compare the data to the real limits for that a/c.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">(...) my tables certainly aren't required in order to succesfully level bomb and I can't see that another table containing good general bombsight data would be a bad thing. Not a bad thing at all. </div></BLOCKQUOTE>

Agree, but since your tabbles are there, fully tested and working pretty good, why not use them? There's no point in re-inventing the wheel.

My idea is simple. To call it a table or chart is sort of overstating. I just would like to learn bomber speed limits (in the game).

That said, if there's a good bomber-test-pilot out there who would like to do this together, just let me know.

I'm afraid I do not posses the required CEM skills to not compromise the data. When testing, I could be not-reaching the top speed due to my lack of proficience with CEM.

What do you say?

Crash_Moses
08-07-2007, 02:41 PM
Fortunately (or unfortunately as the case may be) CEM in this sim really isn't very complex...at least not like the real birds were.

What I did when I was developing my tables was try to find the slowest speed at the slowest RPM and lowest throttle setting I could without sinking with the level stabilizer enabled. Then I just worked my way up from there.

My reasoning behind that of course is that the PBJ didn't bomb at cruising speed (they sped up just before reaching the target) and they didn't max out the engines either. It was important to baby those Allisons...

So I don't think what you're proposing would be difficult...just time consuming. Unfortunately I'm way too busy at work/home at the moment to help out. In fact, next Sunday I'll be off on a business trip to Tijuana for two weeks...after that...Las Vegas! http://forums.ubi.com/images/smilies/partyhat.gif And my current obsession, UDPSpeed (http://forums.ubi.com/eve/forums/a/tpc/f/49310655/m/7201027043?r=8531099975#8531099975), is sucking up quite a bit of my time...

However, if I did have the time I think I'd work on filling in the remaining altitudes of my chart...there are still a few gaps.

But you know what I'd really like to see? A formula that determines the optimum speed and engine settings with a given load at any altitude. Bombsight Table 2 (http://www.checksix-fr.com/bibliotheque/index.php?page=detail&ID=2547) came pretty close but it's still fairly inaccurate.

S!

PakoAry
08-08-2007, 12:34 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Crash_Moses:
(...) And my current obsession, UDPSpeed (http://forums.ubi.com/eve/forums/a/tpc/f/49310655/m/7201027043?r=8531099975#8531099975), is sucking up quite a bit of my time... </div></BLOCKQUOTE>

Crash_Moses, your current obsession well deserves every second it's sucking. Very interesting this UDPSpeed... I'll not branch the topic and I'll get more informed first, but it really caught my attention.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> But you know what I'd really like to see? A formula that determines the optimum speed and engine settings with a given load at any altitude. Bombsight Table 2 (http://www.checksix-fr.com/bibliotheque/index.php?page=detail&ID=2547) came pretty close (...) </div></BLOCKQUOTE>

I thought Bombsight Table 2 were used only to calculate angles for manual drops (+ IAS/TAS convertions).

Anyway, thanks for the tips, enjoy some local tequila in Tijuana and keep up the good work. :-)

Crash_Moses
08-08-2007, 01:09 PM
Roger that! http://forums.ubi.com/images/smilies/25.gif Thanks!

Yup, that's all Bombsight Table 2 could do. But it wasn't very accurate. In fact, there's a chart around here somewhere that shows corrections for the BT2 figures. If I can find the link I'll post it here.