AvHistory.org

The Wheels of Progress move forward

gregoryp — Sun, 25 Nov 2007 21:41:00 GMT

Finally we’ve got the Assembly Line moving and I’ve sent the first aircraft to Bear to QA. The 4.0.164, or “164” as we call it is such a massive step up from all of our previous efforts. New is using the all the physics to predict performance. This brings us much closer to our intended goal, accurate flight performance of the aircraft. Our process is different from others who rely on anecdotal data and fudges to make the aircraft fly like whoever yells loudest. If you go to their message boards you...(read more)

Dad, are we there yet?

gregoryp — Tue, 13 Nov 2007 05:00:00 GMT

Been a while, I’m supposed to do these more often.

I’ve got family member in the Hospital ICU so most of my time has been spent at the Hospital. I’m still amazed I was able to get an interim flight model done to meet the MAW release last June.

For those of you not familiar with having a loved one in the Hospital, it sucks! You’re day is basically sitting around hoping the Doctor pop their head and say something positive. Plus keeping your inner feelings inside so you remain strong for other family members that need your support. The thing that rips you up is the patient goes through major swings of getting better, getting worse. Up, down, up, down. No slow straight recovery like in the movies.

Here in the US, you go to an acute care hospital first. Once they get you stable, you’re shipped off to a Long Term Recovery Hospital, or worst case a Hospice. The difference in quality between the two is amazing. You get the feeling that your loved one has been sent off to die so the Acute Care Hospital doesn’t get a bad tick mark. It’s not true, but that’s what it feels like.

Since I don’t have a Laptop, it major sucks. With no computer, I can’t work on the aircraft. You wouldn’t believe the aircraft backlog. The visual model developers have been very patient. When the Hospital visiting hours are over I rush home, take care of the kids who have been super through all this, tuck them in and jump on the computer. Work until I drop and then start a new day. How the MAW aircraft got out while doing this I have no idea.

Anyway, at least I bring my Aero books with me and we’re now up to a 4.0.163 release. I’ve been able to finally get the process to the point where we can enter the aircraft data and let the DATCOM, new Lifting Line code, and a bunch of other code grind along and spit out the aircraft flight model. What makes this interesting is the physics are well known and allows us to separate the BS from reality. Fingers crossed we can all approach this as scientists looking for the truth and not the “my favorite plane has to be better than everyone else’s” like on a lot of message boards out there!

As an example, we have this new climb prediction code. You feed it a lot of data and it predicts the max climb rate of the aircraft. It’s very accurate. I was working on the F4U-4 (one of the gang of 10 test aircraft) and the numbers just didn’t jive with the performance chart in America’s Hundred Thousand. In the end it tuned out the chart contained data for the –18W and –42W engines. Different HP's, different rates of climb. Other things I’m seeing is inconsistency in max rate of climb listed in all the publications. Some use max weight, some combat weight, some 85% power, others combat power. When you see this value listed in the books you have to ask what was the speed, weight and HP used (plus a bunch of other little things) to record it. There were some aircraft that if you used the book values you’d be totally off from what the real aircraft could do. Which unfortunately all the commercial releases use these values. So there should be some interesting discussions in the future.

Anyway, slowly getting back to catching up. There is a lot of work to do. We should have the 4.0 releases starting to flow off the assembly line soon. Bear has some nice new skin his texture artist have done.

AvHistory, MAW and Beyond

gregoryp — Fri, 06 Jul 2007 19:36:00 GMT

Wow, it’s hard to believe we finally got MAW (http://www.medairwar.com/) out the door. Plus using our new version 4.0.159 DATCOM/Roskam based flight models. I just want to thank all the Desert Rats for the fun time during the last 3 years. And I’m looking forward to more as we develop the following chapters. We’ll be updating the MAW FM’s to version 161. This version pushes the CFS/FS 6-DOF flight equations about as far as they can go. To go further requires a full blown 6-DOF flight sim like JSBSim (currently there is no combat sim using it).

In parallel with MAW activities we will be doing:

Conversion of our own AvHistory aircraft (thank you developers for being patient).
FM’s for the Battle of France (BoF) group
FM’s for the Korea group
And most likely FM’s for a rumored China/Burmese and Solomon Islands theaters

Last is to get the user measurement program working. DATCOM/Roskam uses geometric measurements of the aircraft. Currently we use 3 view drawings and a custom measuring tool to pull measurements off. There is no reason the actual aircraft could not be used, which would also be the most accurate. So the plan is to create a procedure people can use to make all the measurements of the real aircraft (with the owners permission).

We’ll be using this feature to Blog different issues and experiences in the Air Combat Community.

Enjoy