After completing the Air Race Jet, I found that the upper fan door does not close completely (stopping short by about 1/2 inches) when I switch from VTOL to Flight mode.

The attachment points to the pulley pieces operating the door seem correct, and the engine nozzle and flaps move into their correct positions.

So I have not been able to see what is blocking it. Any ideas on fixing this?

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I did notice that the two gray pieces that support the black engine nozzle cowl are shown as upright in the instructions, but are slightly slanted in my completed model. I wonder if this may be related.

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Yesterday I contacted LEGO customer service about my non-closing fan door problem, after disassembling about 30% of the model in a vain effort at finding the cause. Their response was that there was nothing wrong and this was normal, even after I sent them Youtubes showing normal operation and a video of my issue.

So in addition to asking for any input on fixing my problem, I’d like to also ask anyone familiar with this kit if you agree that there is a problem.

Well, I decided to call customer service at LEGO, and a very helpful fellow confirmed the existence of the defect in my model — doubtless a mistake buried somewhere in the 1,151 parts, as I thought. So back to my question - where should I look for the defect?

He suggested focusing on the area depicted below. You’ll notice a yellow crossbar going through two gray support pieces. With the doors shut, they should be flush against one another with none of the yellow showing, but in my model they have a gap when Flight mode quits, as shown. If you manually push the doors (top or bottom) shut, they are flush. So this area may be key, or (shudder) just an artifact of a mistake elsewhere.

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2 Answers 2


I don't have this model. Never built it, but thanks to Youtube we can understand with moving pictures the frustration, and build fatigue you might feel.


"It's one of those builds where you need to get everything exactly right the first time. Penalty for making any sort of mistake is very very high and there are many things that are left incomplete for long periods time as you're building up the functions inside of this.

The main build of all of the gears, and all of the levers, all of the beams, and everything that connect together, ultimately, very very late in the game, late in the process of building to form the functions that are all powered by a single motor."

enter image description here Think Loud's video review and speed build, is similar to your issue, where his fap door doesn't close properly, and he has to manually pop it down too. So, I see what you mean, Bro.

I'll take your word that all connections are good, so we're not gonna think it's, an

"artifact of a mistake elsewhere."

(Luv how you said that!)

So, in trusting you, I think your build is right instruction-wise, but our engineering insight could use a slight twist here and there.

So, in this Vertical Take-Off and Landing mode, we see:

  1. Top blue flap comes up.
  2. Two bottom blue flaps spread open.
  3. Rear gray exhaust nozzle drops down.
  4. Two black flaps on back of wings that turn down.

enter image description here enter image description here enter image description here enter image description here

For all of these features to work properly, you have to go back to your build, and manually turn each section, or gear torque completely to position "0" of VTOL mode.

So, if one or more is off, even slightly, it will affect the total length of deployment, and retraction of the others.

I can only imagine one of the features positioned too early hitting a physical wall, or space constraint, causing the other features not to fully complete their run.

You did mentioned the top gap, bottom gaps, and misaligned tail engine. Yes, they're all related to the VTOL feature so, if one is off, they're all gonna be off.

Try this out, and hit us back with your results.

My source videos:

  • Thank you for your thorough and thought-provoking comments, all of which are very much appreciated. The most valuable portion of your commentary to me is where you reference Think Louder’s identical problem with the fan turbine door. Bingo! Identical to my issue. So I guess there is no getting around executing a disassembly and reassembly of much of the model, which I shall now undertake. I will indeed report back on my results. – Jul 23, 2018 at 7:02
  • 1
    You’re welcome, my Friend. Hey, before you get deep in the disassemble, run your model as is, a few times, and visually look at those (4) hot spots to see which one doesn’t have the room to complete it’s full diployment run. Note: LEGO has been trolling us in this way for years. All of us can follow instructions, but LEGO wants us to understand our work too. The engineering mistakes force us to observe the cause, and see the effect. JANGBRiCKS showed us how it should work and look by end run. Another thing: Listen to the shift change in sound as the moving parts winds down. Later! Jul 23, 2018 at 19:18

Check step 63 There is in zoomed picture showed when small black wheel has to be connected to beige wheel,when connected it will "lock" the position of closed roof and bottom To correct it when u already built it is very easy Move that small black wheel from beige ,u added in step 63. When black wheel moved,press the "L" lever in red box zoomed picture down,your roof and bottom will close,when closed hold the position and move black wheel back to connect with beige, now it should work pretty well

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