Jump to content

Top speed of the R-27ER

LetMePickThat

By LetMePickThat
in Weapon Bugs

 Share

Recommended Posts

  • 2 weeks later...
FoxAlfa

FoxAlfa

Posted
Posted

It would be interesting to see how this values compere to the ones in DCS 🙂

  • Like 1

-------

All the people keep asking for capabilities to be modelled.... I want the limitations to be modelled.... limitations make for realistic simulation.

Arguing with an engineer is like wrestling with a pig in the mud, after a bit you realize the pig likes it.

 

Long time ago in galaxy far far away:

https://www.deviantart.com/alfafox/gallery

tavarish palkovnik

tavarish palkovnik

Posted
Posted

It would be indeed (for this and these), but that and those probably you don’t have extracted.

However when I see that, for example H-58, is powered with lousy 210s in march, and this rocket is filled with highly energetic composite fuel, and plus to that with 195s in buster 🤔 , everything can be expected.

 

tavarish palkovnik

tavarish palkovnik

Posted
Posted (edited)

It is very hard to animate anybody in this very interesting stuff, even here nobody want to talk 😐

I thought R-27ER is rocket of interest here, at least I got such impression.

Anyway I will continue with some more words, at least it will be at one place.

So now when having Cx f(M ; H) at zero angle of attack and Cy f(M) also at zero angle of attack and some allowable angles, it is good time to use these numbers for cases when rocket is under overload, when angle of attack starts to be involved.

This is simplified mathematic but sufficient enough. So let’s take one time moment, 1km and 2M.

Cx0-drag coefficient at zero angle of attack

Cy0-lift coefficient at zero angle of attack, 1/deg

Cx1-drag coefficient with angle of attack

Cy1-lift coefficient with angle of attack, 1/deg

A-angle of attack, deg

Cx0=0,713 ; Cy0=0,5079 ; and for example A=5 deg

Cy1=Cy0-Cx0/57,3=0,5079-0,713/57,3=0,495 (1/deg)

Cx1=Cx0+Cy0*A^2/57,3=0,713+0,5079*5^2/57,3=0,935 

Edited by tavarish palkovnik
  • Like 3
tavarish palkovnik

tavarish palkovnik

Posted
Posted

These are not random stuffs, these are sequences in order to get answers. I would like, if there is no in free sources full description, and there is no, to get answer how this rocket actually flys. Also I would like to find someone with same enthusiasm (I’m not rocket scientist) to share thoughts. I was reading here lot about R-27, mostly complaints, so I guessed there will be someone, however.

If there is no any single photo and drawing of R-27ER than why not to make one by itself. Collecting visual segments and textual descriptions in assembly is possible isn’t it. With knowing how it looks and what is inside it’s easy to describe how it works. Than it is hard to convince me in something else. 
Further sequences are ballistic characteristics, all that can be calculated, just regular physics and mathematics, some books, some tables, calculator and there it is…source.

Next sequence is guiding method together with all previous (not random) and there it is…answer is there. Conclusion is there. 
 

  • Like 2
GGTharos

GGTharos

Posted
Posted

Your work is appreciated, I think it's pretty awesome how you constructed the rocket motor using available information and knowledge.

[sIGPIC][/sIGPIC]

Reminder: SAM = Speed Bump :D

I used to play flight sims like you, but then I took a slammer to the knee - Yoda

  • 1 month later...
  • 3 weeks later...
El Chapo

El Chapo

Posted
Posted (edited)

Hello,

As I mentioned it earlier in MP, very interesting work. I just had time to look at it deeper, and try to understand more clearly what you did.

I still however have a doubt about your drag and lift coefficients, do you mind discussing it?

I am just plainly looking at other available sources, for different missiles.

Regarding the old V-625 rocket, we have Cx0 = around 0.2 at M 1.5 (per square meter)

With ED's model from the paper shared before, we have Cx0 = around 0.15 at M 1.5 (per square meter)

With V2 rockets, we have Cx0 = around 0.42 at M 1.5 (see here: https://www.researchgate.net/publication/254288747_Early_Warning_in_South_Asia-Constraints_and_Implications) (per square meter)

With your own models:

We have Cx0 around 0.8 at M1.5 for R-27 (both versions) and Cx0 above 1 for R-73.

So my question is: why would these Cx0 coefficients be that much higher than for other missiles, even older ones that have not been optimized for supersonic speed (eg: V2) . Do you think that aerodynamics is that different that it could explain a times two Cx0 coefficient?

Thanks for your hard work!

I'd love to see that type of research done on more missiles 🙂

Edited by El Chapo
tavarish palkovnik

tavarish palkovnik

Posted
Posted

Don't mind to discuss it at all.

Drag force ''Fd'' = Drag coefficient ''Cx'' * dynamic pressure ''q'' * Referent area ''Sref''

As you can see, I always try to specify together with Cx what is referent area for calculated drag coefficients, and mostly it is body cross section area instead of fixed values like square meter or something else.

0,8 for Sref 0,05307m2 is roughly 0,0424 for Sref 1m2. Roughly because it doesn't go that way exactly 

 

  • Like 2
  • 3 months later...
  • 3 months later...
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...