My FX-3 Build

[Neal]

5 point harness lower anchor

 

[turbopilot]

I doubt I could tell a difference at my experience level. I’ll let you know when I get the numbers from TacAero. As they are crazy expensive on everything I’m not optimistic. For now I’ll enter holding. My research is done. My options have shaped and now it’s wait time.

Trent told me the 5 point harness was $1945. Ouch but like BRS it’s a safety feature. Needed? Don’t know.

If you run the numbers I would be interested in how it comes out.

 

[turbopilot]

5 point harness lower anchor

My comments will be made on the assumption the anchor for the roll control torque tube assembly in that image is the same as on the SS. It looks identical from this view, but I can't see underneath. If it is the same as the SS this is not a "hard point" for a restraint system. This is a relatively thin carbon fiber structure that supports the battery box and the seat above. I would guess maybe 5 ply carbon fiber composite structure.

Here is what it looks like from the belly looking up through the access hatch into the box just in back of the strap anchor. In this image you see the left side of carbon fiber box. Along the top you can see the aluminum roll torque tube coming from the stick to the left. The arrow is pointing to what I think is one of the two bolts holding down the torque tube clamp. On the right of the image (which toward the rear of the airplane) is the autopilot roll servo. That is why I know this area very well. You can see a 4130 fuselage tube running across the upper right part of the image. That would be the right place to attach that 5th strap as a hard point. In an accident those two bolts holding down the current attach point would just pull through the carbon fiber composite.

Side note I see this airplane has stainless steel brake lines that you can see coming out of the box on either side of the stick.

 

[turbopilot]

I doubt I could tell a difference at my experience level. I’ll let you know when I get the numbers from TacAero. As they are crazy expensive on everything I’m not optimistic. For now I’ll enter holding. My research is done. My options have shaped and now it’s wait time.

Trent told me the 5 point harness was $1945. Ouch but like BRS it’s a safety feature. Needed? Don’t know.

You will be flying the bottom of the line Sport Cub which should be standard cub gear with bungees in place of AOSS or Acme. I have never flown bungees but I understand they are miserable for bouncing. If you get to TRM you will fly Beringer. If you bring my airplane down from YKM you will fly AOSS. So with luck you may be able to fly all options except Acme. Maybe when in YKM you can snag a ride in an Acme airplane. Then you will be the expert.

Check out Aircraft Spruce seems to be many 5 point harnesses for much less money. I would like to get a 5 point so I will begin head scratching to find a way to secure the center strap. I am thinking a cable from each 4130 tube either side of the belly hatch access up to the same place it is attache now in that image you sent may be the answer.

 

[Neal]

I will not be flying my plane with basic gear. It will be delivered to Hood River by CC that way and then TacAero will change out the gear and all then I'll fly it and do the remaining of the 40 hrs. Jeremy will probably fly it once as received from CC for the acceptance inspection he'll do on my behalf as he has all the experience of what to look for inside and out. He could probably wait and fly it after the gear is complete in fact, shouldn't matter to CC if the gear has been improved, he'll inspect paint, engine, electronics, sensors, etc.

 

[Schwbo]

I'm highly interested in your arrangement with TacAero. Can you please share Jeremy's contact details. I call him as well.
I'll start a new discussion on my own build. Just got the dates from CC.

 

[Neal]

@Tsquared - for the 5 point harness, do you feel there is a sufficient mechanism below the seat where they attached the harness for a seatbelt restraint? @turbopilot had some concern as to what they were anchoring to.

 

[Tsquared]

Gentleman,

the 5 pt harness is installed post certification so I never saw how it’s mounted. My original request was for a 5pt for both seats, but I was informed there was no mount point suitable for the aft seat. Take that for what you will. Keep in mind that one of the main functions of the 5 strap is to keep the lap belt down on the hips and prevent the hip belts from riding up on the abdome. On that point it works well.

 

[turbopilot]

Gentleman,

the 5 pt harness is installed post certification so I never saw how it’s mounted. My original request was for a 5pt for both seats, but I was informed there was no mount point suitable for the aft seat. Take that for what you will. Keep in mind that one of the main functions of the 5 strap is to keep the lap belt down on the hips and prevent the hip belts from riding up on the abdome. On that point it works well.

@Tsquared welcome. Yes, that is one reason for the 5 point. Another reason is to prevent "submarining" under the belt with sudden deceleration. I want to install one of these belts so I will be looking for a way to make it work to a hard point. There are hard points under the rear floor for the rear seat but it would require a hole in the floor.

 

[Tsquared]

The battery I was referring to is an antigravity XP3 (link below). The intent is to use this to jump start things on the ground in the event the main starter battery dies on you. My experience with flying a flight schools CC LSA in the winter is that the battery isn’t that strong. the first start in the morning was ok, the second start that morning had problems. After lunch we had to hand prop it. if you go with this get the clamp less harness that allows you to plug in the battery vs having to rotate the pilot seat up to use the alligator clips. You can see the connection in the 5 pt harness picture Neal posted.

the starter problem I was referring to was I’m told that CC got a bad patch of starters that would fail. I’m told the problem was resolved and the starters being installed now are good to go.

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[Tsquared]

@Tsquared welcome. Yes, that is one reason for the 5 point. Another reason is to prevent "submarining" under the belt with sudden deceleration. I want to install one of these belts so I will be looking for a way to make it work to a hard point. There are hard points under the rear floor for the rear seat but it would require a hole in the floor.

thanks Turbo. agreed on the preventing submarining aspect. Personally I hate having my lap belt ride up my abdomen reminding me I need to lose weight....

 

[Tsquared]

Regarding the 80/26 vs 83/29 question. Mission drives the gear. Most of the guys I’ve meet who own FX3 are not taking $300k+ planes into hard back country. I have no doubt there are guys who do that, but I’m not one of them. Are you really going to take your plane into a situation where a 200ft per minute climb is the difference between getting out or putting it into a tree? If the margin of error is that tight.... Be it a 200ft per second climb rate or a 100 ft takeoff difference, most of the time I doubt you’d be able to notice a practical difference unless your high altitude, high DA or high gross weight, Or all three. If your going to do STOL competitions than the 83” prop would be the way to go.

For me, my mission is a fun tail dragger I can fly where ever I want to. 80/26 meets those requirements. The iFR panel is another level of safety in case things go pear shaped and you find your self in IMC. Granted good pre flight planning should keep you away from IMC but ive had enough experiences where weather came up that was not in the forecast. Knowingly flying into IMC at freezing temps in most GA aircraft isn’t stupid, it’s suicidal.

To turbos point on the 80/26” combo vs the 83/29” combo. Show me the data. Short of objective data the only way we’re going to get real data is to but a 80/26 next to a 83/29, set them to the same weight and put data loggers on them.

 

[Neal]

The battery I was referring to is an antigravity XP3 (link below). The intent is to use this to jump start things on the ground in the event the main starter battery dies on you. My experience with flying a flight schools CC LSA in the winter is that the battery isn’t that strong. the first start in the morning was ok, the second start that morning had problems. After lunch we had to hand prop it. if you go with this get the clamp less harness that allows you to plug in the battery vs having to rotate the pilot seat up to use the alligator clips. You can see the connection in the 5 pt harness picture Neal posted.

the starter problem I was referring to was I’m told that CC got a bad patch of starters that would fail. I’m told the problem was resolved and the starters being installed now are good to go.

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This sounds exactly what @turbopilot was telling me with the 340 engine and Carbon Cubs where they are hot after flying and get hard to crank and people kill the batteries in the process. Maybe @turbopilot can explain this better but it sounds what you've observed. I'm not sure if this is a problem in the FX3 with fuel injection, it may be a carb engine issue?

I am opting for the heavier duty SBS-J16 battery, I'm hoping with this we wouldn't need the option you added but I added it to my amazon shopping list for later consideration. As @turbopilot found this J16 battery is much cheaper aftermarket at about $190 vs. CC's $450 I asked Jeremy from TacAero. He said yes, order this with your plane so it's all wired in, etc. I guess it's not a simple swap later as some wiring may need to be done.

 

[turbopilot]

You should have bought Dave's airplane. What a sharp guy.

 

[Neal]

Haha. I didn’t not buy it because of him. Perfect plane terrible timing.

 

[turbopilot]

Yup, but I would much rather call Dave than CubCrafters is I had a question or a problem.