Hatz Biplane Association

Hi Alex

Something you said in one of your posts caught my attention and is probably worth a comment. Hope I am not preaching to the Choir. I would certainly want to investigate the W&B issue but even before that, if the airplane has never been certified is there paperwork (or photos, or both) to prove the airplane is in fact amateur built? This sounds trivial but can be a headache as you will be required to prove to the FAA or a DAR that the airplane was built by an individual or group of individuals for the purpose of education or recreation (or words to that effect), in order to obtain an airworthiness certificate. We had an individual locally (some years ago) that bought a completed (but never inspected or certified) homebuilt with no paperwork. The local FSDO was reluctant to certify the airplane, although I do not remember the outcome, I think he parted out the airplane to recoup some of his money.

I am a DAR and have been asked to inspect and certify homebuilt aircraft with little or no paperwork. I can usually work with the owner to find enough "evidence" to convince me the aircraft is in fact amateur built, but I need to see something. A builders log is best, but a notorized statement from the previous owner/builder will sometimes suffice. If the current owner has no such "proof" you are possibly purchasing an aircraft that cannot be certified as amateur built. Of course different DARs will have a different take on what can be done, even though we try to standardize the process as much as possible.

Hope I am not ranting about something you already know and appologize if I am wasting your time.

Regards

Dave

Now this makes sense!

Thanks, Doug ... and thanks to Randy for posting the CG range solution.

Any comments from other Hatz builders?

Alex,

Please have a look at the builder page for Randy Brooks' Hatz (http://www.hatzbiplane.com/535.html ). That page contains a link to the W&B work he did. Perhaps it may help.

Paperwork from the certification - AHA! ... but therein lies the rub.

The airplane was built, a registration issued in 2001. 13 hours appear somewhere as having been flown but no Airworthiness Certificate was ever issued. I'm sure there is a reasonable explanation for all that and I'm waiting to delve into it further. The part of the story I've been given so far is that there were the inevitable events that winnow away partners from any project; retirements, moves, deaths, etc., and the airplane now resides in the midwest in a yet to be determined condition.

I'm forever an optimist and am looking forward to an in-depth investigation ... the w&b question is part of my due diligence to determine whether the airplane and I will fit together.

Part of my really interesting discovery so far is that I have to learn how to calculate a w&b for a biplane! Any help with that would be gratefully received as well.

Thanks for your note, Bill ... interestingly, Doug writes that there doesn't seem to be a document that lists the w&b limits for a CB-1. I guess that's because as experimenters we are all test pilots and have to develop our own w&b and performance data, although I've never encountered an airplane design that didn't have calculated data.

Alex

I do not have specific info; however, the Hatz has no Wt&Bal issues that I know of. The Pax and the fuel are pretty much on the CG so they don't affect things much and the pilot does not have that large an effect either. As long as the paper work from certification is in order you should not have any issues. Best of luck.

Bill

I'm looking at buying a CB-1 and would like to know the CG limits for the airplane. Is there a form somewhere (maybe somebody has a handy spreadsheet on the forum?) or would someone please walk me through calculating a W&B before I go trotting off 1000 miles to look at this airplane?

Thanks

Alex