Javron Stock Pa18 wings with PSTOL

[tackdog]

Hi everyone. I'm at the stage of my build where I'm fitting my PSTOL flaps to the Javron stock round tip wings (larger tanks with 3 tank straps).

Airframes sent the wing prep kit to Jay where the doublers were installed at wing assembly - for the false spar doublers. A set of doublers also
arrived with my FLAPS in their shipping crate - the 2 hangar type with the one inboard pushrod for experimental.

Whilst fitting up one of the the flaps last night, I noticed the 'rib flange doubler' that comes with the airframes kit - but didn't notice one installed on the wings with the other doublers. Is anyone aware if this particular piece isn't used in a Javron Wing, as I realise there are some subtle design changes between the wings?

Its not a difficult doubler to fit - but I have to remove some other rivets first. I would ring Jay - but don't really want to stay up late to catch the time zones from down under!

Thanks

 

[Steve Pierce]

I doubt Javron did any independent structural testing of their wing with the P-STOL flaps so I would install the parts that came with the flaps since Airframes Alaska did structural testing.

 

[DENNY]

having the full length inner doubler I think is key. The reinforcement is pretty easy to add on so most likely worth it. Gregg pushes things to the limit so he's a good testbed.

 

[Steve Pierce]

having the full length inner doubler I think is key. The reinforcement is pretty easy to add on so most likely worth it. Gregg pushes things to the limit so he's a good testbed.

tackdog is referring to the rib flange doubler not the flap hanger doubler. I bet there is a lot more force on Greg's at 70 degrees vs the 50-55 degrees that flaps were designed to be operated at. The certified flap hanger reinforcements I have installed are far beefier than those experimental brackets.

 

[Scott A]

FWIW, I have talked with Jay about that rib flange doubler. He says its not needed on his and they do not install it. It did not come in my box from Airframes. Having said that if I had the part I may put it in as Steve said.
Also the slide in flap hanger bracket reinforcements on my experimental are the full length solid ones - I've never seen those little half things that bent on Greggs.

 

[tackdog]

Thanks for the replies. My ‘hanger bracket doublers’ also came as the full length solid ones. Wow, those experimental ones Greg showed are a LOT different

 

[Scott A]

Thanks for the replies. My ‘hanger bracket doublers’ also came as the full length solid ones. Wow, those experimental ones Greg showed are a LOT different

Yeah, I don't think there is any difference between what you get now with certified vs experimental. Those originals for sure looked wimpy.

 

[DENNY]

FWIW, I have talked with Jay about that rib flange doubler. He says its not needed on his and they do not install it. It did not come in my box from Airframes. Having said that if I had the part I may put it in as Steve said.
Also the slide in flap hanger bracket reinforcements on my experimental are the full length solid ones - I've never seen those little half things that bent on

I was on a trip out East trying to post on my phone, back home now so I will try to do the rest of the story. As I remember the shorter flap hanger brackets came with the original PSTOL flaps. The reason Greg had a big tray of tshorter ones is because he was making them for Airframes. Once the video came Airframes got a lot of calls wanting the longer ones so I believe they are all shipped with the long one now. I don't recall anyone other than Greg posting issues with the short ones but once they video came out everyone wanted the long one. As far as the rib flange doubler Airframes was only supplying them for experimental kits if requested. This was a few years ago but I think I have the story straight. I had just ordered my flaps when the video came out and got both the doubler and the long hanger bracket reinforcement, Everything is still waiting to be installed. I normally don't worry about weight, however as I ponder this is the rib flange doubler really needed once you have the flap hanger bracket in place? It appears the flap hanger bracket was the weak point in the past. Making it stronger will move the stress down the line but with Jays boxed false spar is it just more weight that is not needed?? If I was adding them to a stock wing I would use the doubler for sure. I have not seen any posts with issues leaving them off. I will try to call around and see if anyone noticed any issues. Do right or wrong just a story and pontification over morning cub of joe.
DENNY

 

[Scott A]

I was on a trip out East trying to post on my phone, back home now so I will try to do the rest of the story. As I remember the shorter flap hanger brackets came with the original PSTOL flaps. The reason Greg had a big tray of tshorter ones is because he was making them for Airframes. Once the video came Airframes got a lot of calls wanting the longer ones so I believe they are all shipped with the long one now. I don't recall anyone other than Greg posting issues with the short ones but once they video came out everyone wanted the long one. As far as the rib flange doubler Airframes was only supplying them for experimental kits if requested. This was a few years ago but I think I have the story straight. I had just ordered my flaps when the video came out and got both the doubler and the long hanger bracket reinforcement, Everything is still waiting to be installed. I normally don't worry about weight, however as I ponder this is the rib flange doubler really needed once you have the flap hanger bracket in place? It appears the flap hanger bracket was the weak point in the past. Making it stronger will move the stress down the line but with Jays boxed false spar is it just more weight that is not needed?? If I was adding them to a stock wing I would use the doubler for sure. I have not seen any posts with issues leaving them off. I will try to call around and see if anyone noticed any issues. Do right or wrong just a story and pontification over morning cub of joe.
DENNY

Thanks Denny. Yes, I think I had gathered from another video of Gregg's that he was machining the parts for Airframes. And yes the power of the internet or social media - even if the original standard brackets are 'okay' for 99% of us - after seeing that I would not want them

At this point I think I'm staying as is and going without the rib flange doubler - but I will probably still have rib flange doubler envy when I see one that has it. I'm hoping to start covering soon so unless I hear through the grapevine that they are really needed I'm pressing on.

 

[tackdog]

Another quick question about the PSTOL flaps install and the flap gap seal that comes with the Airframes kit. I see from stock wing setups, that the gap seals are typically painted, and pk screwed into place after covering. Is there a reason not to rivet the Airframes gap seals into place? I haven't got to the fabric covering yet, and wasn't sure if I glued fabric over these and the surrounding parts, that they would buckle badly once the fabric was shrunk in other areas or not? Any thoughts?

 

[skywagon8a]

Another quick question about the PSTOL flaps install and the flap gap seal that comes with the Airframes kit. I see from stock wing setups, that the gap seals are typically painted, and pk screwed into place after covering. Is there a reason not to rivet the Airframes gap seals into place? I haven't got to the fabric covering yet, and wasn't sure if I glued fabric over these and the surrounding parts, that they would buckle badly once the fabric was shrunk in other areas or not? Any thoughts?

My gap seals are made of balsa wood glued over the fabric and covered by a fabric strip.

You can see both trailing edges here. The balsa was shaped by using the flap as a sanding block. The teflon tape was put on to prevent any possible chafing between the flap and wing.

 

[Steve Pierce]

I would not cover over the gap seals on the P-STOL flaps. Be hard to keep the under camber attached and sometimes they need to be tweaked a bit to keep from rubbing on the flap itself.

 

[Scott A]

I also asked Jay about that some time ago. He said what Steve says - he recommended to not rivet and not put them on before cover.

 

[skywagon8a]

I'll add, mine have been installed for more than 12 years. The fabric is stuck to the balsa with Stewarts glue and there has never been any change indicating a tweak is warranted. The conventional aluminum, riveted or screwed in place parts could act as Steve describes.

 

[DENNY]

Whatever way you do it I would leave them off and the wing uncovered until you do a test fit and rigging on the fuselage to check for clearance issues especially if you have them extended inboard. Basically build the entire aircraft without cover including glass and cowling so you can find all the issues before you cover and paint. It takes more time but cutting fabric and repainting because a flap was 1/4 in too long or tail angles are not right really sucks!
DENNY

 

[Steve Pierce]

I'll add, mine have been installed for more than 12 years. The fabric is stuck to the balsa with Stewarts glue and there has never been any change indicating a tweak is warranted. The conventional aluminum, riveted or screwed in place parts could act as Steve describes.

The problem is you are not dealing with a solid piece of balsa or even a piece of formed aluminum. It is two pieces of aluminum riveted together with a long flat piece of .020 to .025" sticking out. Sometimes they have to be tweaked to fit the gap.