Scoop vs snorkel

[Taltruda]

I?m no where near ready to make this decision, but I love the look of the 7 or 8 without the scoop. Are there any benefits either way? Does the engine breathe better with the scoop, maybe more ram air? Or are there speed increases from the drag reduction? Does the snorkel in the left intake reduce the airflow into the cowl causing hotter cht?s? Or is the type of induction (Carb vs Injection) dictate which intake the plane goes with?

[Ed_Wischmeyer]

I asked Van's about that and the loss of ram air pressure is worse than the drag reduction. Scoopless looks better, flies slower.

[robertahegy]

Scoop or Snorkel is purely a matter of opinion as far as aesthetics. I sort of like the scoop myself. Either way, it is an RV and has to be BEAUTIFUL.

Roberta

[Desert Rat]

I don't know the number from vans, but the James cowl has a snorkel and they claim a 1" increase in manifold pressure over ambient at 5,000'.

[DanH]

Originally Posted by Taltruda

I?m no where near ready to make this decision, but I love the look of the 7 or 8 without the scoop. Are there any benefits either way? Does the engine breathe better with the scoop, maybe more ram air? Or are there speed increases from the drag reduction? Does the snorkel in the left intake reduce the airflow into the cowl causing hotter cht?s? Or is the type of induction (Carb vs Injection) dictate which intake the plane goes with?

As a practical matter, a snorkel means the cowl is easy to get on and off.

The manifold pressure difference isn't huge. A buyer can do either choice badly or well, shifting the performance balance.

Vertical induction engines (may be carb or injection) almost always use an airbox fed by a forward facing intake. Horizontal induction engines (typically injection) may use either a forward facing intake or the snorkel from the left cooling intake.

[JohnInReno]

Originally Posted by DanH

As a practical matter, a snorkel means the cowl is easy to get on and off...

If you split the scoop intake material so that half is connected to the lower cowl, it makes it much easier to remove the cowl.

[chaskuss]

Originally Posted by Taltruda

snipped
Or is the type of induction (Carb vs Injection) dictate which intake the plane goes with?

The snorkel [smooth cowl] is used on fuel injected engines with forward, horizontal mounted fuel servos. The IO-360-M1B & IO-360-A1A are two such engines. Use of a Bendix pressure carb could also use this set up.

Charlie

[DanH]

Originally Posted by JohnInReno

If you split the snorkel intake material so that half is connected to the lower cowl, it makes it much easier to remove the cowl.

That's an airbox for a vertical induction engine. A snorkel links a horizontal induction to the left cooling air inlet.

As for those seals on the airbox inlet....leakage there pressurizes the lower cowl volume, reducing deltaP, and thus reducing cooling capability. Make sure they seal well.

[Bill Boyd]

Work in progress. SCAT will be trimmed to length and terminated with a ring of self-fusing silicone tape to mate with the FAB opening.

[Bcone1381]

So having a scoop adds negligible drag? Can you put a drag penalty on it? If we get more MAP, thus more HP, we are burning more fuel too.