Jump to content

Cranking the fuel


ph-kim
 Share

Recommended Posts

I noticed that quite a lot of wubble pump action is required before you get to the required 2.5-3.5 lbs of pressure required. According to the plane manual, only 3 or 4 strokes were needed to build up enough pressure, so that seems a bit excessive.

I'm also not entirely sure about the bottom limit. I haven't been able to actually start the engine with only 2.5 lbs indicated on the gauge, but that might also have been just lack of proficiency on my side.

Link to comment
Share on other sites

Hey ph-kim!
I believe you are mistaking the wobble pump actuation with the primer actuation.

I'll link you a video of a real PT-19 startup procedure (It is in portuguese, but the important thing to notice is how many times the pilot pumps that wobble pump):

And on your other question: You actually need a bit less than 2.5 PSI. 2.5 is listed in the manual in order to give you some margin on that setting, this is because fuel pressure escaped through the fuel pressure relief valve (you can observe this happening if you build up pressure, and go check the bottom cowling's opening. It will be dripping this pressurized fuel). I believe what happened is that you took a bit longer than expected to start the engine after the pressure was built.

Hope this was somewhat insightful!
Dan.

Link to comment
Share on other sites

image.thumb.png.d2a60ceb1113e1162547f2ca7f041d15.png

No I wasn't confusing the primer with the wobble pump, I've highlighted the part in the manual about it above (and by plane manual, I wasn't referring to your manual, but the real world one). But yes, that YT clip clearly shows a lot more 'wobble pump action' is required there.

The time between building pressure and starting could have been the issue, although I uses the 'make her cranky' helper button, so there wasn't much delay.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...