Grumman AA1B

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Shrek
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Grumman AA1B

Unread post by Shrek » Tue May 11, 2010 1:55 pm

Hi There
Can anyone help me. I am the owner of a grumman AA1B. She`s got a Lycoming 0-320 engine 150hp and weighs 1650 pounds. The prop is a prince Mccauley 1a105. It seems I cannot get my rpm over 2160 max and indicated airspeed of 108 kt. I am not the technical guy so please can anybody give advice as it seems the prop needs to be changed.
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Theuns v V
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Re: Grumman AA1B

Unread post by Theuns v V » Tue May 11, 2010 6:40 pm

I don't realy know this setup, but what does the manual say abuot the engine/prop combination?
If it is the right prop, was the pich "changed" at one stage to make it more corse? It should in throry be in the prop's logbook.

It sounds that the engine is labouring under the prop and not not developing full power.What are the hours on the engine, still new?Maybe it could be a restriction in the air induction somewhere, I am just guessing.

Good luck

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Re: Grumman AA1B

Unread post by flysouth » Fri May 14, 2010 4:22 pm

Hi Shrek - I am very familiar with the Grumman line of light aircraft - I owned one from 1977 - 1993 and in 1994 bought two wrecks to build up into one with Chev engine - see http://www.flysouth.co.za

Your Grumman at least has the right engine - the original 108hp Lyc was good for sea level ops but not so terrific at high elevations two up on a hot day!- you should be getting at least 130 - 140 MPH TAS at 2500 - 2700 (redline).

Which AA1 do you have? There are only a few in SA that have had the 0-320 conversion done - all of them under my Mod Approval except one - this might be yours if it is the conversion done by Sundrew Strima at FAWB.

As long as your motor is running well, then you should see about getting the prop re-pitched - when I took out the 0-235-C2C motor on my aircraft and replaced it with the 0-320-A2B with Sensenich prop, I got 1500 fpm climb out of FACG (5250 amsl) but only about 110 MPH max speed at redline! That prop was pitched at 60 inches (Model 74-DM-0-60) and after repitching to 66 inches, I saw 900 fpm with 130 MPH @ 2500 rpm cruise revs. The late Theuns du Toit from Propeller Shop at FAWB did mine.

At sea level, right on the waves and pulling 2800 rpm for a short time, top speed was 165 mph.

My prop allowed me to run up to 2700 rpm at 7000 feet which was exactly what I wanted as that was the height that most of my flying is done at!

Repitching metal props is a process that shocked me when I watched it done by Theuns - after clamping the prop on the bench with a cuff clamped around the blade attached to a lank steel gwala, three guys bear down on the bar while Theuns measured the twist on the prop - quite brutal, but effective and apparently no harm to the prop - I flew mine for at least 1000 hours afterwards without problems.

Having written all this I see you mention a 'prince' McAuley prop - not familiar with that, (or is Prince just the supplier of the McAuley prop?) the original Grumman AA1 came with a McAuley metal prop, but that would not be any good with your bigger engine - altogether too small for that power.
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Re: Grumman AA1B

Unread post by Theuns v V » Sun May 16, 2010 8:45 am

[quote="flysouth"]Repitching metal props is a process that shocked me when I watched it done by Theuns - after clamping the prop on the bench with a cuff clamped around the blade attached to a lank steel gwala, three guys bear down on the bar while Theuns measured the twist on the prop - quite brutal, but effective and apparently no harm to the prop

I had the same done to my Sensinich on the L-18, WAS SHOCKED to say the least, , but I wanted 200 rpm extra and that was what I got -first time. That was "old school" :D

Just make sure that your prop can be reworked, as I understand not all can.please correct me if I am wrong :oops:

T
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Re: Grumman AA1B

Unread post by Shrek » Mon May 17, 2010 10:04 pm

Hi Flysouth
Excellent, just the info that I needed. Yes you are correct , my Grumman serial number is 206. modified by Wonderboom AMO Sandro . It seems like I need to change the prop the. The engine is still new, 200,9 hours.... :D her previous callsign was ZS-IXO . It changed before I took ownership last year 29 may 2009 and it is ZU-FCG. Do you know where I might get more info on a more correct POH. Whom would you suggest I must take her to for the prop.?? :?: Was this weekend at Carnavon Fly -inn. Four hours and nine minutes later it was no go for her. I could not start her again. So my idea is that something is wrong with the magnetos. (newly painted and I cant think that both will go at the same time except after a service :?: :?: :?: :?: please tell me I'm wrong. 8-[ Do you know any of the other grumman owners in RSA and where are they based???
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Re: Grumman AA1B

Unread post by flysouth » Mon May 17, 2010 10:56 pm

Hi Shrek

Yup - I knew your airie when it was IXO IIRC. What is your Mod Approval number? I have Mod 85/361 - I registered that Mod with CAA in 1985 when I put the 150hp engine into my original AA1A.

I know personally two other Grumman owners here in Gauteng - they both have modded AA1Bs, with 160hp motors, extra tanks etc etc - and one has further modified his airframe for aerobatics (+6G/-3G) with CAA approval. You might have guessed we are a bunch of Grumman-lovers of long-standing here! - I never met a more honest little airie and I love the way they are constructed - that honeycomb and spar could save your life one day like nothing else can!There has never been an in-flight structural failure of a Grumman AA1 anywhere - ever and a guy I know in the US tested the spar to 16.7Gs for the FAA - but it remained undamaged! No permanent deformation from that test. Another friend put his Grumman ZS-WEE (originally ZS-IXI) into the ground nose-first after take off at Harrismith - and he and his girlfriend survived with minor injuries.Airie was a write-off though!

I cannot believe that both your mags can fail at the same time - there has to be something else! - however if the impulse coupling which is necessary for starting a Lycoming (impulse is on on the left mag I think) has failed that could be the problem. as a first step Why not pull off ALL the plug-leads (so the motor cannot fire) and check for a spark as you rotate the prop?

I would suggest that you speak to Propeller Centre at FAWB (Theuns' son now runs that shop) about repitching the prop you have - just as a guide I asked Theuns to pitch my Sensenich prop so that i would have full-throttle max revs (2700 rpm) at 7000ft amsl - that worked perfectly for me and luckily that prop could take that much coarsening. He also balanced the prop at the same time and that made a significant difference to smooth running.

If you do need to get a new prop for any reason, know that my mate with the aerobatic AA1B at FAWB has a Sensenich wooden prop on his airie - and reports that it is just great - he especially likes the light weight of it when compared with the weight of the metal McAuley it replaced - better for his aerobatics. Also it costs about 50% of the price of a new metal prop!

I have a 3 blade Warp-Drive prop on my Chev - engined AA1B - works great on the ground (has not yet flown), pulls like a bull and can be ground-adjusted for pitch too. Weighs just 11 lbs and costs about R10 500 landed in SA! Fits the standard SAE2 prop hub bolt pattern that you probably have.

I see you are in Kuruman - do you have anyone there for props? I was there many years ago collecting a Cessna 140 which the EAA bought as a club plane from a local doctor and there were no maintenance facilities if I recall - maybe that changed?

At BaraG there is my Grumman and Trevor's 160hp deluxe rebuilt machine - let us know next time you are coming our way, you should pop in and you'll see you some good Grumman stuff.

On the POH - let me have a scout around as I may have a copy of the original somewhere.
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Re: Grumman AA1B

Unread post by davelo » Thu May 27, 2010 2:44 pm

Hi guys. I own a (largely original) AA-1B based at Vereeniging (ZS-IXJ). If you need the owners manual PM me your email address. It's a large file though, despite not being a particularly large document itself - approx 5MB!
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Re: Grumman AA1B

Unread post by flysouth » Mon May 31, 2010 11:56 pm

davelo - I am still searching for an old copy of the POH - no luck yet - if I cannot locate it maybe I could ask you to send yours to me as I will have to manufacture a modified version for my airie for the CAA.
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Re: Grumman AA1B

Unread post by davelo » Tue Jun 01, 2010 8:36 am

flysouth, just PM me your email address and I'll send a copy off to you.
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Re: Grumman AA1B

Unread post by flysouth » Wed Jun 02, 2010 6:28 pm

Thanks Dave - still searching right now, I know I left it around here somewhere! :roll: - will contact if I do not come right!

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Re: Grumman AA1B

Unread post by Grapilot » Wed Jul 17, 2019 8:39 pm

Hello,
I am restoring a Grumman AA1 and looking to upgrade the cylinders tolycoming high compression O-235-L2C cylinders. I am looking for a McCauley A105 propeller like the one you are not able to use for your O-320 engine configuration.
If it is still in your possession I may want to acquire it.

Thank you.

Gerard.
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Re: Grumman AA1B

Unread post by flysouth » Wed Jul 17, 2019 10:30 pm

Grapilot wrote:
Wed Jul 17, 2019 8:39 pm
Hello,
I am restoring a Grumman AA1 and looking to upgrade the cylinders tolycoming high compression O-235-L2C cylinders. I am looking for a McCauley A105 propeller like the one you are not able to use for your O-320 engine configuration.
If it is still in your possession I may want to acquire it.

Thank you.

Gerard.
Gerard, the original McAuley prop off my airie was sold as a unit along with the 0-235-C2C motor after I did the 150 hp engine swap. Also I know the same prop off the late Trevor Trautmann's AA1B was also sold. So cannot help there sorry.

I do have moulds to make sets of wheel pants though. On the higher powered Grumman these gave me around an extra 8 mph!

Regards,

Stewart

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