Comments - XL Jabiru CHT's - Zenith Aircraft Builders and Flyers2024-03-28T08:29:36Zhttps://zenith.aero/profiles/comment/feed?attachedTo=2606393%3ABlogPost%3A163730&xn_auth=noI also experienced high CHT's…tag:zenith.aero,2011-10-05:2606393:Comment:1645872011-10-05T23:48:58.737ZPhillip Owenshttps://zenith.aero/profile/PhillipOwens
I also experienced high CHT's on my Jabiru 5100 8 cyl engine. when we checked the airflow we found that because the air intake design from Jabiru was angled backwards from the center outwards and also from the bottom of the opening to the top. Result, the upward movement of the prop was driving the intake air over the opening instead of into it, resulting in high CHT's on the left bank. I made an aluminum lip and rivited it to the top of the left intake and the result was to bring down the CHT…
I also experienced high CHT's on my Jabiru 5100 8 cyl engine. when we checked the airflow we found that because the air intake design from Jabiru was angled backwards from the center outwards and also from the bottom of the opening to the top. Result, the upward movement of the prop was driving the intake air over the opening instead of into it, resulting in high CHT's on the left bank. I made an aluminum lip and rivited it to the top of the left intake and the result was to bring down the CHT temps of the left bank to almost match the right bank. We were also very careful to provide a 3.5:1 air exit ratio to intake when we made the cowl since we knew in advance that was the minimum, we also made sure the point of exit was aft of the firewall. This small detail is very important to prevent a high pressure zone inside the rear of the cowl. We have been informed that most all Jabirus run high CHT temps until at or after the 25 hr break in period, we noted lower temps as the engine was run. Hope this is of some value to you. I had problems initially, wit…tag:zenith.aero,2011-10-04:2606393:Comment:1643612011-10-04T20:31:11.075ZRobert Emeryhttps://zenith.aero/profile/RobertEmery
<p>I had problems initially, with CHTs (now flown 25 hrs) in Australia where we get high OAT's. I played around witrh the inlet ram air ducts, but found most change when I woorked on the outlet area.</p>
<p>I have increased the size and angle of the outgoing air cowling area. By creating a lower pressure here the air is drawn through as per Jab website info. I also found that sealing air intake and around air cooler had a beneficial result. I am now running CHT's of around 120 to 140 degres…</p>
<p>I had problems initially, with CHTs (now flown 25 hrs) in Australia where we get high OAT's. I played around witrh the inlet ram air ducts, but found most change when I woorked on the outlet area.</p>
<p>I have increased the size and angle of the outgoing air cowling area. By creating a lower pressure here the air is drawn through as per Jab website info. I also found that sealing air intake and around air cooler had a beneficial result. I am now running CHT's of around 120 to 140 degres C (I think that equates to 250 to 285 F)</p>
<p>Max is on centre cylinders at around 300F, but by climbing at 90 knots I keep it under this. I will post some pics when I get a chance</p>
<p>Regards</p>
<p> </p>
<p>Bob Emery</p> Great values !
1.3.6 Cylind…tag:zenith.aero,2011-10-02:2606393:Comment:1637972011-10-02T20:49:43.415ZAlberto Martinhttps://zenith.aero/profile/AlbertoMartin
<p>Great values !</p>
<p> </p>
<p>1.3.6 Cylinder Head Temperature (CHT)<br/>Maximum Peak Cylinder Head Temperature1 ......... 200ºC (392°F)<br/>Maximum Continuous Temperature ........................ 180ºC (356°F)<br/>Note: Time with CHT at between 180°C and 200°C is not to exceed 5 Minutes</p>
<p> </p>
<p>At least, that is what the manual says...</p>
<p>Great values !</p>
<p> </p>
<p>1.3.6 Cylinder Head Temperature (CHT)<br/>Maximum Peak Cylinder Head Temperature1 ......... 200ºC (392°F)<br/>Maximum Continuous Temperature ........................ 180ºC (356°F)<br/>Note: Time with CHT at between 180°C and 200°C is not to exceed 5 Minutes</p>
<p> </p>
<p>At least, that is what the manual says...</p>